Thought I would post this in here, as its mainly for the trad crowd. I always found with scrapers they rust, and trying to get blade out to replace was a pain. You drop them from height then they jam up etc. Anyway I cam across these a few years ago, I am still using the same one, i do have around 10 in stock though HA http://www.maplin.co.uk/mini-scraper-225918 You get a cap, and to replace the normal scraper blade its just turning that black screw. It fits in a green unger bucket in a belt and the ninja one (same i know) PS I know it says mini, but they are roughly the same size as normal metal ones.