[gavi]

...to remedy this problem?

[MitchHellman]

Move the litter box to where they have been peeing. If necessary, buy more than one box if there is more than one place they've peed in.

[maamu]

Try a different brand of litter.

Or keep the litter you have and get rid of the cats.

[melkhel]

I always put my liter box in the bathroom. Try keeping them shut in there with it for a while until they learn where it is at. If they pee somewhere else it is tough but rub there nose in it and lock them in the bathroom for a time out for a while. Make sure that there is water and something familiar in there for them so they can get used to it with trama. Stay patient cats take a while. They have their own attitude. Make sure you clean where they peed really good and don't use amonia. There is carpet cleaner for this and lysol cleaner for the rest of the stuff. They smell it they will do it again.

[Monkey]

How old are they and how long have they been doing this for? It may take a while for them to learn where to get rid of their waste, when they pee on the floor just give them a tap on the nose and after he's done peeing bring him next to the litter box and tell him to pee there.

He'll eventually learn that he has to get rid of waste in the litter box.