I have recently removed a washable wallpaper from a downstairs loo. The top layer of paper came off more or less in one piece leaving the lining / backing on the wall. I sprayed this with warm water using a plant spray bottle, let it soak in for 5 minutes and then used a large putty knife to remove the wet paper. Very, very easy! I then washed the wall to remove the remains of the old adhesive, let it dry and put on a couple of coats of emulsion in the normal way. I was very pleased with the result - and so, surprisingly, was Mrs ZZ