[OS X TeX] Remove extension from the "Delete aux files" list

[Sime Ungar]

Hello,
every once in a while one has to trash the aux files because something got corrupted. And this is easily done in TeXShop from the File menu or Cmd+Ctrl+A. But this deletes everything except .tex and .pdf files. I would like to keep the .ind file as well. How do I remove it from the "Delete aux files" list? 
(I know that with 'defaults write TeXShop OtherTrashExtensions -array-add "foo"' I can _add_ the .foo extension to the list, but is there a "remove" variant?)

Namely, I am writing a book in Croatian having an 18 page long Index. Since Makeindex is an ancient program not knowing anything about Unicode and in Croatian there are 8+8 graphemes (letters) which are not ASCII, the sorting of many index entries is wrong. So I have to tweak the .ind-file every time the aux files are trashed, which becomes quite tedious.

Best,
   Sime