OMG, trying to remove that awful caulk which dries as hard as stone but grows mold like a Petri dish from around my second story windows. Putty knife too weak, double edged scraper broke, enter this puppy: which can be worked with two hands! It even easily removed my blotches from brick after 6 hours. Also did a number on glue for carpet tack strips on a tile floor... what a project. Ah, the right tool...
Note carbide blade. Some just add a thin piece of steel. The groove has edges on either side and helps hold it tightly.
Click on top image for link to carbide scraper.