When I clean my geldings' sheaths, I feel like I'm not getting everything out. The smegma usually comes out in tiny bits, like the size of a pencil eraser, and there's usually around 20-30 of them. But when I reach up in there again, I feel like there's still a bunch of nastiness in there. Thing is, I can't really get it. It just kind of is... mushy, I guess? And even when I try to scrape it off, it won't come out. How can I make sure I get everything?