I have a slow leak behind the toilet pan between a concertina fixing and a solid plastic waste pipe. Don't think they are lined up particularly well - the joint is smothered (1 inch thick) in some white sticky stuff (I think it might be plumber's mait????) Bathroom was installed (before I bought the house!) by a DIY bodger (don't start me on the no of problems I've had.... to give an idea he moved the cistern to make it concealed - but neglected to move the overflow or change it for an internal overflow - I didn't know I had a problem until the ceiling downstairs caved in... ) Now at breaking point - I have concluded that the whole bathroom needs to be ripped out and redone ... But I need a bodge to stop it leaking while I get quotes/plans/etc/etc ... So is the white gunk plumber's mait? Will it work? Can I just put more on top or do I need to get rid of some of the old stuff first? Is there an easy way of getting rid of the white gunk?