Litter Training Potty trainned guinea pigs?

Short answer -- you can't. What you can do is put their hay bin over their litter pan, and that'll catch most of the poop and pee. And you can put extra pads where they sleep, so that you can change those out more frequently. Some pigs sorta train themselves, and those owners are lucky, but there's not much you can do one way or the other.

I will say, if they do choose to use a corner litter pan or something like that, don't make any changes to their routine. Mine came to me using a corner litter pan a good part of the time, and had been raised with aspen both in their cages and in their litter pans. I switched them to fleece, and they totally ignored the litter pans from that time on.

I have tried it but it seams impossible. Mine just wont do it Hopefully you'll have more luck!

Some pigs go to the bathroom in one area so something you can try is putting the litter box in that area. Some pigs will totally ignore it, and some pigs will use it. It's just luck. I keep my hay in a hay rack over a litter box filled with bedding, and the rest of my cage is fleece. My pig uses her litter box the majority of the time except there are usually a few poops where she sleeps. It would be amazing if a guinea pig only used their litter box, and never went to the bathroom anywhere else, but I don't think it could really happen.

When I had an upper loft to my cage, Nikki would always "go" in one corner, right under the ramp. I was thinking of cutting a small piece of fleece or something absorbant to put there and just change it every day to keep the cage fresh, but I never got around to it.
If your pigs use one spot as a potty more than others, try putting a litter box there. I've heard that sometimes pigs will move their bathroom area when a litter box is put down, so don't get your hopes up just yet. Fingers crossed it works though.

thanx everyone, i ll deal with this when Torres get better! THank you for ur helpfull ansewrs