I too have the same problem. I have tried scraping it, wetting and scraping and I was told to heat it up with a butane torch to soften the glue. That worked, but just as labor intensive as scraping. Plus, the emissions off teh heated glue and burning paper are not desireable.
If you find a better way, drop me a line as well. I have 3 bathrooms and a kitchen to do quick!!!