Yes we bought us a new litter box and this was to say the least, vehemently rejected by our Plütis. I would not run at this point further, but it was quite a mess. Then the toilet and the area around it easily sprayed with Feliway and lo and behold, suddenly no longer an issue. Initially thought really, the stuff would Hocus Pocus; was more of a desperation purchase, but in the end we were amazed. Clear recommendation, also recommended to travel very, the stress level of all living beings on board reduces immensely.
