There are cappers sold that hold up to 100 percussion caps at a time, which you use to dispense the caps directly onto the nipple. I don't remember the last time I dropped a cap. Check the website for Track of the Wolf, or Dixie Gunworks. Tedd Cash makes two different kinds of cappers, and in addition, you can find inexpensive straight line- or " stick " cappers that will hold about 20 percussion caps. I started with one of these sticks, but it exposes the caps to lint, and the elements, and I soon replaced it with one of the Tedd Cash cappers.
The nipple should be cleaned between shots with a cleaning patch and some spit. Its free and works as well as any of the "solvents" sold. I used to move the hammer back to the half cock notch, remove the spent cap, then clean the nipple with a fresh cleaning patch with spit, before unending the gun, and putting the same patch over the muzzle. Then I would run it down the barrel to remove the powder residue as part of my between shots cleaning routine. When the barrel was loaded, and the ramrod was put aside, the last thing I did was put a new cap on the nipple to ready the rifle to be fired. It was a very fast, and efficient way to clean my gun and make sure the gun would fire the next shot. I still use the same technique when loading and cleaning my percussion DB shotgun.