diff --git a/lib/chunks/chunk.rb b/lib/chunks/chunk.rb
index 9beb0e6c..02b2eb9a 100644
--- a/lib/chunks/chunk.rb
+++ b/lib/chunks/chunk.rb
@@ -61,7 +61,7 @@ module Chunk
     end
 
     def unmask
-      @content.sub!(mask, @unmask_text)
+      @content.sub!(/#{mask}/){|s| s.replace @unmask_text}
     end
 
     def rendered?
@@ -73,7 +73,7 @@ module Chunk
     end
 
     def revert
-      @content.sub!(mask, @text)
+      @content.sub!(/#{mask}/){|s| s.replace @text}
       # unregister
       @content.delete_chunk(self)
     end