diff --git a/Library/Homebrew/cleanup.rb b/Library/Homebrew/cleanup.rb
index 3629630231..854ca577be 100644
--- a/Library/Homebrew/cleanup.rb
+++ b/Library/Homebrew/cleanup.rb
@@ -84,7 +84,7 @@ module CleanupRefinement
       resource_name = basename.to_s[/\A.*?\-\-(.*?)\-\-?(?:#{Regexp.escape(version)})/, 1]
 
       if resource_name == "patch"
-        patch_hashes = formula.stable&.patches&.map(&:resource)&.map(&:version)
+        patch_hashes = formula.stable&.patches&.select(&:external?)&.map(&:resource)&.map(&:version)
         return true unless patch_hashes&.include?(Checksum.new(:sha256, version.to_s))
       elsif resource_name && resource_version = formula.stable&.resources&.dig(resource_name)&.version
         return true if resource_version != version