either a #32 drill bit or 1/8" drill bit, i use it to cut the carbon out of the plugs flash hole and then use a Q tip with somes hoppes black powder solvent on it to wipe the face of the plug and inside the primer pocket.
A better way?
Dyna Tek Gun Shield!
You degrease the breech plug with rubbing alcohol or such and dry it off. Once dry you go and dip " or wipe" the gun shield onto the plug. I feel its best to dip it into the solution for 100% coverage. Once you've dipped the plug, allow 20 to 30 minutes to dry and then repeat this process 2 more times " 3 to 4 coats is recommended"
Allow the plug to sit and cure for a couple hours before placing the plug on a cookie sheet in a preheated oven @ 350*. Bake the Gun Shield onto the plug for 45 minutes to 1 hour.
The next time you shoot, at the end of the day you will find that the fouling will easily wipe right off with simple water, windex, what ever you normally use to clean!
It protects against rust, corrosion, mud, dirt, basically what ever gets onto the gun, will not harm it.
http://gandersmuzzleloadingblog.blog...-dyna-tek.html
Heres a video i shot after i applied Gun Shield to the frame of my CVA Accura and got it real dirty on the range.
http://www.youtube.com/user/frontier.../0/u6klwwA56DE
They have kits now that do one rifle for around $10. Its a great investment and actually protects your firearm.