male cat not using litter box

Question
We have two neutered male cats about 2 1/2 yrs old.  We have two litter boxes side by side for them.  Recently we caught one of them urinating in a basket of clean clothes.  The next day he urinated on a pile of sheets waiting to be washed.  Last week it was their basket of play toys.  They both get to go outside some every day.  Any idea what would trigger this?  (We did go out of town last week & had someone come in & feed them & clean the litter boxes.)

Answer
when my cat was young he used to do the same thing, but now that hes older and got yelled at alot he doesnt do it any more. What you can do is if the litter box has a lid then take it off, it makes the smell worse for the cats. The only other things you can is make sure the litter box is clean and dont leave any piles of clothes laying around.