Nope-don't even think about putting a putty scraper in the dishwasher. I've seen people try it, and it never ends well. Let me tell you why. First, metal scrapers (stainless steel or carbon steel) hate dishwashers.
Dishwashers use super hot water and harsh detergents-this can strip the protective coating off stainless steel, making it more likely to rust. I had a friend who put his stainless steel scraper in the dishwasher; next time he used it, there were rust spots all over the blade. He tried to clean 'em off, but they just got worse.
Then there's the handle. Most putty scrapers have rubber or wood handles-dishwashers will ruin those. Rubber handles get soft and sticky, like melted gum, and wood handles absorb water and start to crack. I once put a small plastic scraper with a rubber handle in the dishwasher (by accident!)-the handle came loose, and the plastic blade warped from the heat. Total waste of a perfectly good scraper.
Even if your scraper is all plastic? The dishwasher's heat can warp the blade, making it useless for scraping. Plastic scrapers need to stay at room temperature-hot water bends 'em out of shape. And let's be real, dishwashers don't even clean scrapers well. Dried putty or paint will just bake onto the blade in the dishwasher, making it harder to clean than if you did it by hand.
Save yourself the trouble-clean your scraper by hand with mineral spirits and warm soapy water. It takes 2 minutes, and your scraper will last way longer. The dishwasher's for plates and cups, not tools!
