Whether or not to clean your eggs before setting them is really up to the personal preference of the person incubating. I've heard many say "don't clean them at all", others say "clean off the visible debris on the egg", and some say "completely clean the egg in a solution", but all of them will say they have 95-100% hatch rate using their cleaning/no clean methods. So far, I have yet to actually find evidence supporting one claim over the other if terms of hatch rate, but people will defend their methods to the death and claim their way is the best/only way! I would try each method and do what you find works the best. If cleaning works for you, do that. If not cleaning works, then do that. Though, as a general rule of thumb, if you have really dirty eggs, you should clean them or just not use them. But some will argue you need to clean all eggs, whether they look clean or not.
I personally don't clean my eggs at all before setting. I make sure to only put my naturally cleanest eggs in though, I don't put in eggs that are caked in dirt and poop. I do this for both my incubator and my broody hens, and my hens have hatched all the eggs they're given, if they're fertile.