Tricky situation.
The 2 male cats belong to my DD2 & her ex. They broke up in November (but are still on amicable terms) - she came home & he went back to his mum's flat with the cats, but the flat is small & the cats (then about 8 months old) were scratching the leather chairs. DD2 will be moving in with a friend quite soon but her house is being slowly done up & it won't be for several more weeks if not longer.
So they came here, but I have 2 cats too (female), & the 4 of them have been living in a sort of armed truce, all of them quite stressed (& me too!)
DD's cats were based in her bedroom & my cats in the back room/kitchen; occasionally they would take it in turns to have the run of the house, occasionally they would all be out together, but there was a lot of suppressed hostility (no actual physical fighting) & now I have a kitten too, currently based in my bedroom, so the musical rooms situation was taking its toll.
His mother has now gone away for a month, so as he's there on his own he offered to have them there while she's away; but they've only been there a couple of days & are scratching the chairs again (of course 
). I suspect part of the problem is that it's not big enough for them to hurtle around & wear off some energy. They have got 2 scratching posts.
He's tried putting a throw over one chair, but one cat wrestling with the throw made even more scratches.
Would clipping their claws help or would that just make wider scratches?
How about tying strips of carpet over the chairs while they're in the room?
I really don't want to go through introducing them back here again.
Any helpful suggestions?