She used to just rip it off the wall. But that's the stuff that comes off easy. I agree with Henry (as usual). Get a paper tiger use it liberally. Get some DIF, I like the gel, and use it liberally. I use a brush, not a roller. Make sure you leave it on long enough (not to long or it will dry). And scrape, away. Try not to damage the wall. I made the mistake of letting a friend take some down, unattended, in one of my bathrooms. Butcher!
Seriously, I have removed the stuff in almost all the rooms in my newly purchased house. Just keep at it.