This is a simple retractable scraper that uses razor/utility blades as an insert. Its fully 3d printed, and is simple to use. It can stand up to light and medium work, however extreme force risks breaking the retainer clips, which can always be replaced. 

Tips-

• The parts can take a few minutes of fiddling before they slide smoothly, it will become much easier to retract with use or jiggling. 
• The blades slide in from the side, they are not pushed in from the front directly.

The one shown was printed in Hatchbox Black PLA.

Haven't printed it in anything else, but I'm sure it will work fine.