I took over a grill and the inside door of the 2 fryers and filter machine are caked in grease. I mean big time! I was able to boil out the fryers but the amount of grease inside the doors is incredible! I can scrape but its so bad that scraping isn't taking it off. What can I use to get years of grime to come off? The filter machine is the same way. Just caked on everywhere and a scraper can't get to all of it. It's a huge sticky mess and nothing seems to be working. Any suggestions?