i have two male kittens of 6 months. one is a pro at using the litter tray, he never misses or soils in the house. the other one poos on towels or curtains on a twice weekly basis. they have been to the vets and neither of themhave anything worng with them physically. i have noticed that he only goes on clean items whichhave just been washed. i keep the tray clean and dont change the litter brand! the tray is close to the back door so they can get to it easily.i am not sure A) what else i can try and B) how i should deal with his behavior when he does it.

HELP!

thanks Annie (Reuben and Henry)