Where to put skin sets

I've been putting skin sets in /sites/all/skins, which has been working well. However, now we need to use drush make in our distribution profile, and it isn't able to create a skins folder. I thought it was okay to relocate skins inside the themes folder (for instance: /sites/all/themes/mytheme/skins/blocks), but the .info file is getting picked up and the skins are now appearing in the list of themes on /admin/build/themes .

Do you have any suggestions on a "drush-makeable" spot to place skin sets in D6?