I wouldn't choose brass. No place for a battery! I think you can buy some sort of elaborate "French Tickler" with a lubed feather duster on the front but if I was leaving them in for any period of time I'd go the cheap route, punch the primers out of a couple of plastic Activ hulls and replace with erasers from a BIC mechanical pencil and wouldn't hurt to grease em up with RIG or Ballistol or something. Would be adequate for a workaday 2 buck and a half gun. I still think the best case is to NOT leave them in chambers.

jack