It sounds like they need sharpened (not surprising they get dirt ion them when used on a horse and used outdoor) and sprayed with a lubrication. Also a dog groomer story here. My boss used to keep two sets of each size, and switch off. She used W-D40 as lube, and had some kind of blade cleaner that you dunk the blade into and turn on. Sorry I don't think I ever looked at the tub to see what it was called.