I have a piece of CC that is going with a Sim for upload. The problem is simple:
- At one point I accidentally created several different presets for the item.
- When placed in the folder that it used to be in, these presets re-spawn, even though I deleted and recreated the designs in CTU, and have deleted the CAS part cache.
- When placed in another folder, they aren't there anymore.
Now I have all these presets that won't delete.

In-game created presets are stored in the userPresets.package file in your user data folder. These are the ones created and saved with the cast-tool, not the ones that come with an item. They are specific to your game, no one else will have them. If you want to get rid of them you need to either delete them with the cast-tool in game manually, or delete the userpresets.package file. But the latter will result in you losing ALL ever saved presets, on clothes, objects, walls etc.

If that doesn't solve your problem, please elaborate on "the folder that it used to be in" and "another folder".

So those duplicate presets only apply to me? Okay, thank you. I was more worried about the user downloading this item getting spammed with them.

You can easily test if these are your own ones or not - just move the userpresets.package to your desktop and start a game. If they are gone, it's something that affects your game only. If they are still present, it's your CC. You can move the package back after the test and replace the one spawned by the game.