I have an Enviro M55 Insert. Part of my weekly cleaning is to slide the raking bar back and forth above the heat exchange tubes. This usually results in a small amount of ash falling down. I have noticed that if I literally slam the bar forward or back, I could get a lot of ash deposits to fall down. But, this slamming back and forth would most likely result in breaking or cracking something, probably structural and that would be real bad. I have tried an assortment of brushes but none seemed to work. Yesterday, I went to my local Brew maistro (1st Republic Brewing Company and Homebrew Supply Store) I had just left the bar to check out the beer making equipment and then I saw all these high quality cleaning brushes of all different sizes, perfect for cleaning above and around the tubes. These pics were taken before I tried it out....but yeah, it works great, especially the area above the tubes. So instead of going to the box stores, seek out your local home brew establishment, check out their cleaning brushes and enjoy a locally brewed craft beer or two!! Bill