The best option I've found is to use a Lewis Lead Remover Kit. It's a safer option than the drill method.
Here's what I do that seems to work extremely well.
1. Run a few cloth patches, soaked with your favorite cleaner, through each chamber of the cylinder.
2. Follow up with a dry patch through each.
3. Run the Lewis Lead Remover tool through each chamber, turning about 6 times with light pressure. You'll be able to feel the screen scraping the crud right off. Use a brush to clean off the crud from the screen when you're done.
4. Run a few more cloth patches, soaked with your favorite cleaner, through each chamber of the cylinder.
5. Follow up with a dry patch through each.
6. Lightly oil the chambers.
The trick to making the screens last, is:
1. Don't tighten the adjustment nut too tight on the rubber tip.
2. Don't tighten the tips onto the rod too tightly, so the holes in the screens don't tear out.
They'll look almost as good as new. Once you do it a few times, it should only take you about 10 minutes to complete the whole process.
You can find it at
http://www.brownells.com.
Here's the item number/info:
516-100-038
Lead Remover Kit, 9mm/.38
While you're ordering, get extra brass patches for the future. Each screen will last about 5-6 cleaning sessions, but you might as well get an extra pack while you can. Here's the patch info:
516-200-038
Brass Patches, 9mm/.38
Dean