Recently one of my flat mates has given the all clear for her friend to stay on the couch. He has now been camping in our living room for over a month and the couch smells of his farts.
Katie, Kentish Town
A simple garden hose would easily solve this problem and give the couch a good once over too, but failing that, have you tried sleeping with him? That way you get your couch back and you've isolated the problem to your own bed, giving your flatmates the common space back. You'll be like a flat share martyr! Then all you need to do is carry this on for a few months and break up with him. He'll then be forced to leave. Or possibly move back to the couch. Might be an idea to that garden hose.