In a semi-auto pistol, it's really just a matter of elbow grease. I start with a paper towel wrapped around a finger. Then a brush, either nylon or copper depending on how dirty it is. If you have one of those brushes that are intended to brush out magazine tubes (usually oval shaped), they also make an excellent brush for cleaning feed ramps. If you're shooting lead, you'll not need any chemicals. If you shoot copper jacketed bullets, there may be build up on the ramp, which will require a copper cleaning chemical.