if you want to attempt to correct the content with CTU, try this:
Click on "File" at the top left of the window
Click on "Open"
Navigate your way to your packages folder (mine is under C:\Program Files\Electronic Arts\The Sims 3 High-End Loft Stuff\Mods\Packages)
Select a file/package you want to edit
Click the "Open" button. CTU will load the package file
Click on the "Part Category" tab (see partcategory image below)
This is where you check to see if the item is "checked" for the proper areas: Type, CAS Part Type, Age, Gender, Category, Extended Category, and Other. Depending on what the item is, will also determine which boxes should be checked.
Example: the image I attached is for a Female skirt. so the Type=Body, CAS Part Type=Bottom, Age=YA & A, Gender=Female, Category=Sleepwear - Swimwear & Athletic, Extended Category=Valid for Random, Other=Human.
For making sure an item doesn't show up in the "Nude Category" look under Category and make sure the "Nude" box is NOT checked.
When your finished making changes, Click on the "Commit" button
Click on "File"
Click on "Save"
This should correct the problem with an item showing up where it doesn't belong.
NOTE: Once the sim started wearing an item in the shower, I was not able to stop them. I thought by deleting the .package file it would eliminate the problem. However, when I tried the game again, the problem item was replaced by a Maxis default.
Perhaps, in theory, if you correct the problem item as opposed to deleting it, the issue may resolve itself. Not sure, it that will work or not, but correcting the problem item as listed above will prevent it from happening in the future.
moderator edit: To facilitate future searches by forum members, I edited this post to include the wiki link.