I triede surgical spirit in London but never ever got rid of the smell completely of visiting cats............and they just laughed at the vets sigh.
I now have two birmans who are getting it wrong, front paws in tray and back paws outside.........sigh
I was going to completly wash that part of the carpet and use simple solution and then put some plastic carpet protector down, and because franta particulaily will spray the tiles, stck it up the tiles too........this is in bathroom,,,,,,probably wont work and I cant do at moment.
Mine are not spraying they are trying to hit the tray but are missing so dont think it will work for you Susanne and just dont know how one gets rid of the smell completely, just hate the smell of surgical spirit now lol.
Oh yes someone on vets recommended tonic water for the smell but that didnt work!