Good luck - I got the first one out of Tom by putting him in the bathroom with the tray, he obliged. The next two he had to go to the vets for, as over a week of trying resulted in nothing - he jumped on the settee to use the normal tray one night, and was shut in one room for 6 hours one day and wouldn't do anything!! As Amanda says, it does need to be there relatively quick - my vets actually say within 4-6 hours. Some vets do say it is a better result if they insert a needle in and extract (I do know the proper term, just can't remember how to spell it!!)