Two of our kids get really obsessed with certain things and generally that does not bother me as their obsessions are harmless.
Paul is totally obsessed with cars and trucks and anything else that has a motor, but cars and trucks are what really gets him gong. We have used this obsession to teach him many concepts including colors, counting, size, in front of, behind, inside and out, etc. He lines the cars up and sorts them for hours and he gives them all names. I can handle the cars, no problem.
Hanna sorts things, books, crayons and pencils, clothes, hangers, etc. She also hoards tags from clothes, school papers, contraband, and food. I can pretty easily put up with all of this except for the food hoarding and we have put a stop to that by locking everything up.
She now has come up with a new thing that just about makes me crazy. She is taring the hems out of her clothes, both the t-shirts and shorts. After she gets the hem out then she is destroying them one thread at a time. She has been taking the threads and putting them in her drawer with the hair she pulls out of her head to hoard.
Since I am not much of a sewing expert, I can put buttons back on and patch small holes but that is about all I care to do, it could get rather expensive to pay someone to re-hem these things or to purchase new ones to replace them. Even if I did that she would take them apart again.
I have no idea how I am going to get her to stop doing this. Even though she is supervised all day long she still has free time all night and short of sitting in her room with her there is nothing we can do to stop this. Someone suggested taking all of the clothes away except for the ones she is wearing but she will pull them apart while wearing them and I do not think she honestly cares if she has clothes on or not. Given the chance she would wear the same thing for weeks without even changing them to be washed. We tried this experiment once where we just let her wear what she wanted and after five days in a row without changing and no shower it was just to disgusting and I made her clean up. Now she has to shower every day and I make sure she has a complete set of clean clothes on.