diff --git a/middleman-core/lib/middleman-core/core_extensions/default_helpers.rb b/middleman-core/lib/middleman-core/core_extensions/default_helpers.rb
index 31b8dbcd..aeaaf500 100644
--- a/middleman-core/lib/middleman-core/core_extensions/default_helpers.rb
+++ b/middleman-core/lib/middleman-core/core_extensions/default_helpers.rb
@@ -6,12 +6,11 @@ require 'padrino-helpers'
 
 class Padrino::Helpers::OutputHelpers::ErbHandler
   # Force Erb capture not to use safebuffer
-  # rubocop:disable UnderscorePrefixedVariableName
   def capture_from_template(*args, &block)
-    self.output_buffer, _buf_was = '', output_buffer
+    self.output_buffer, buf_was = '', output_buffer
     raw = block.call(*args)
     captured = template.instance_variable_get(:@_out_buf)
-    self.output_buffer = _buf_was
+    self.output_buffer = buf_was
     engine_matches?(block) ? captured : raw
   end
 end
@@ -39,7 +38,6 @@ class Middleman::CoreExtensions::DefaultHelpers < ::Middleman::Extension
   helpers do
 
     # Make all block content html_safe
-    # rubocop:disable Semicolon
     def content_tag(name, content=nil, options=nil, &block)
       # safe_content_tag(name, content, options, &block)
       if block_given?
@@ -53,7 +51,10 @@ class Middleman::CoreExtensions::DefaultHelpers < ::Middleman::Extension
       output.safe_concat "<#{name}#{attributes}>"
 
       if content.respond_to?(:each) && !content.is_a?(String)
-        content.each { |c| output.safe_concat c; output.safe_concat ::Padrino::Helpers::TagHelpers::NEWLINE }
+        content.each do |c|
+          output.safe_concat c
+          output.safe_concat ::Padrino::Helpers::TagHelpers::NEWLINE
+        end
       else
         output.safe_concat "#{content}"
       end
@@ -72,17 +73,10 @@ class Middleman::CoreExtensions::DefaultHelpers < ::Middleman::Extension
       ActiveSupport::SafeBuffer.new.safe_concat(result)
     end
 
-    # rubocop:disable MultilineBlockChain, UnusedBlockArgument
     def auto_find_proper_handler(&block)
       if block_given?
         engine = File.extname(block.source_location[0])[1..-1].to_sym
-        ::Padrino::Helpers::OutputHelpers.handlers.select do |e, h|
-          e == engine
-        end.values.map do |h|
-          h.new(self)
-        end.find do |h|
-          h.engine_matches?(block)
-        end
+        ::Padrino::Helpers::OutputHelpers.handlers.select { |e, _| e == engine }.values.map { |h| h.new(self) }.find { |h| h.engine_matches?(block) }
       else
         find_proper_handler
       end
@@ -195,10 +189,8 @@ class Middleman::CoreExtensions::DefaultHelpers < ::Middleman::Extension
     #
     # @param [String] path The path (such as "photo.jpg")
     # @param [String] prefix The type prefix (such as "images")
-    # @param [Hash] options Data to pass through.
     # @return [String] The fully qualified asset url
-    # rubocop:disable UnusedMethodArgument
-    def asset_url(path, prefix='', options={})
+    def asset_url(path, prefix='', _)
       # Don't touch assets which already have a full path
       if path.include?('//') || path.start_with?('data:')
         path
diff --git a/middleman-core/lib/middleman-core/core_extensions/request.rb b/middleman-core/lib/middleman-core/core_extensions/request.rb
index 3e822715..bd182fd6 100644
--- a/middleman-core/lib/middleman-core/core_extensions/request.rb
+++ b/middleman-core/lib/middleman-core/core_extensions/request.rb
@@ -124,12 +124,11 @@ module Middleman
         # configuration can be included later without impacting
         # other classes and instances.
         #
-        # rubocop:disable ClassVars
         # @return [Class]
         def server(&block)
-          @@servercounter ||= 0
-          @@servercounter += 1
-          const_set("MiddlemanApplication#{@@servercounter}", Class.new(Middleman::Application, &block))
+          @servercounter ||= 0
+          @servercounter += 1
+          const_set("MiddlemanApplication#{@servercounter}", Class.new(Middleman::Application, &block))
         end
       end
 
diff --git a/middleman-core/lib/middleman-core/extension.rb b/middleman-core/lib/middleman-core/extension.rb
index cff75105..89f4e613 100644
--- a/middleman-core/lib/middleman-core/extension.rb
+++ b/middleman-core/lib/middleman-core/extension.rb
@@ -280,7 +280,6 @@ module Middleman
       @klass.after_configuration do
         ext.after_configuration if ext.respond_to?(:after_configuration)
 
-        # rubocop:disable IfUnlessModifier
         if ext.respond_to?(:manipulate_resource_list)
           ext.app.sitemap.register_resource_list_manipulator(ext.class.ext_name, ext, ext.class.resource_list_manipulator_priority)
         end
diff --git a/middleman-core/lib/middleman-core/file_renderer.rb b/middleman-core/lib/middleman-core/file_renderer.rb
index f3ee6d73..b55cb48e 100644
--- a/middleman-core/lib/middleman-core/file_renderer.rb
+++ b/middleman-core/lib/middleman-core/file_renderer.rb
@@ -20,7 +20,6 @@ module Middleman
     # @param [Hash] opts
     # @param [Class] context
     # @return [String]
-    # rubocop:disable UnderscorePrefixedVariableName
     def render(locs={}, opts={}, context, &block)
       path = @path.dup
 
@@ -32,7 +31,7 @@ module Middleman
       context.current_engine, engine_was = engine, context.current_engine
 
       # Save current buffer for later
-      _buf_was = context.save_buffer
+      buf_was = context.save_buffer
 
       # Read from disk or cache the contents of the file
       body = if opts[:template_body]
@@ -85,7 +84,7 @@ module Middleman
       output
     ensure
       # Reset stored buffer
-      context.restore_buffer(_buf_was)
+      context.restore_buffer(buf_was)
       context.current_engine = engine_was
     end
 
diff --git a/middleman-core/lib/middleman-core/preview_server.rb b/middleman-core/lib/middleman-core/preview_server.rb
index 070b3a37..b855777f 100644
--- a/middleman-core/lib/middleman-core/preview_server.rb
+++ b/middleman-core/lib/middleman-core/preview_server.rb
@@ -2,7 +2,6 @@ require 'webrick'
 require 'middleman-core/meta_pages'
 require 'middleman-core/logger'
 
-# rubocop:disable GlobalVars
 module Middleman
   module PreviewServer
     DEFAULT_PORT = 4567
@@ -35,12 +34,12 @@ module Middleman
           loop do
             @webrick.start
 
-            # $mm_shutdown is set by the signal handler
-            if $mm_shutdown
+            # @mm_shutdown is set by the signal handler
+            if @mm_shutdown
               shutdown
               exit
-            elsif $mm_reload
-              $mm_reload = false
+            elsif @mm_reload
+              @mm_reload = false
               reload
             end
           end
@@ -130,7 +129,7 @@ module Middleman
 
           # See if the changed file is config.rb or lib/*.rb
           if needs_to_reload?(added_and_modified + removed)
-            $mm_reload = true
+            @mm_reload = true
             @webrick.stop
           else
             added_and_modified.each do |path|
@@ -156,7 +155,7 @@ module Middleman
           if Signal.list[sig]
             Signal.trap(sig) do
               # Do as little work as possible in the signal context
-              $mm_shutdown = true
+              @mm_shutdown = true
               @webrick.stop
             end
           end
diff --git a/middleman-core/lib/middleman-core/profiling.rb b/middleman-core/lib/middleman-core/profiling.rb
index d5b43ef4..d7f89bd4 100644
--- a/middleman-core/lib/middleman-core/profiling.rb
+++ b/middleman-core/lib/middleman-core/profiling.rb
@@ -1,22 +1,21 @@
 module Middleman
   module Profiling
-    # The profiler instance. There can only be one!
-    # rubocop:disable TrivialAccessors
-    def self.profiler=(prof)
-      @profiler = prof
-    end
-    def self.profiler
-      @profiler ||= NullProfiler.new
-    end
+    class << self
+      # The profiler instance. There can only be one!
+      attr_writer :profiler
+      def profiler
+        @profiler ||= NullProfiler.new
+      end
 
-    # Start the profiler
-    def self.start
-      profiler.start
-    end
+      # Start the profiler
+      def start
+        profiler.start
+      end
 
-    # Stop the profiler and generate a report. Make sure to call start first
-    def self.report(report_name)
-      profiler.report(report_name)
+      # Stop the profiler and generate a report. Make sure to call start first
+      def report(report_name)
+        profiler.report(report_name)
+      end
     end
 
     # A profiler that does nothing. The default.
diff --git a/middleman-core/lib/middleman-core/template_context.rb b/middleman-core/lib/middleman-core/template_context.rb
index 81d405a8..e321753c 100644
--- a/middleman-core/lib/middleman-core/template_context.rb
+++ b/middleman-core/lib/middleman-core/template_context.rb
@@ -1,7 +1,6 @@
 require 'middleman-core/file_renderer'
 require 'middleman-core/template_renderer'
 
-# rubocop:disable UnderscorePrefixedVariableName
 module Middleman
   class TemplateContext
     attr_reader :app
@@ -16,13 +15,13 @@ module Middleman
     end
 
     def save_buffer
-      @_out_buf, _buf_was = '', @_out_buf
-      _buf_was
+      @_out_buf, buf_was = '', @_out_buf
+      buf_was
     end
 
     # rubocop:disable TrivialAccessors
-    def restore_buffer(_buf_was)
-      @_out_buf = _buf_was
+    def restore_buffer(buf_was)
+      @_out_buf = buf_was
     end
 
     # Allow layouts to be wrapped in the contents of other layouts
@@ -30,7 +29,7 @@ module Middleman
     # @return [void]
     def wrap_layout(layout_name, &block)
       # Save current buffer for later
-      _buf_was = save_buffer
+      buf_was = save_buffer
 
       layout_path = ::Middleman::TemplateRenderer.locate_layout(@app, layout_name, current_engine)
 
@@ -48,7 +47,7 @@ module Middleman
         end
       ensure
         # Reset stored buffer
-        restore_buffer(_buf_was)
+        restore_buffer(buf_was)
       end
 
       file_renderer = ::Middleman::FileRenderer.new(@app, layout_path)