And exactly what? You have not provided any useful info like clone settings, type of footage, version of AE, system info and whatnot nor have you actually explained what "bad result" means in your world. That aside, if you mean to remove/ disguise the loose thread, then conventional masking and effects would be much more adequate, given the low quality of your footage. any attempt at cloning would no doubt only intensify the perception of artifacts.
Thanks, you know what? You're the exact smug reason I don't use forums.....
What exactly is your problem? Don't you manage to get a good result on a single frame? Or is the problem that it looks good on the frame you paint, but not on the other frames? Usually, this kind of paint work requires a lot of manual tweaks.
If you need to paint on a moving object, it often makes sense to use the clone stamp in a stabilized precomp.
This video gets you started:
The clown example in this tutorial (chapter 2) also gives an idea how to do this kind of retouch work: