I've always stored them in their sheaths, but every few years, I need to clean all that green crap off the brass where it contacted the leather. In fifty years of having this kind of knife, I've never had a spot of rust from storing them in their leather sheaths, but I do constantly battle that green crap. Is there a product or some trick to keeping that off the brass?

Zippered padded cases. I never store knives in sheaths.

https://agrussell.com/knife/Zippered-Nylon-Knife-Case-1-3-4-IN-X-4-1-2-IN--CZN-C1442

I make a little cardboard sheath for mine, and store the leather separately. Oil the blade, slip into the cardboard, and then they go into the Ft Knox safe shelves.

I've been told for 50 years never to store my knives in their leather sheaths, and in all that time I've never had a spot of rust on a blade. Only problem I've had was the green crud forming on the brass guards. Which is a pain in the neck to remove, but is not a serious issue.

I'm thinking Saran Wrap might be a solution to the greening issue. Brass only turns green where it contacts leather.

This is the method I use. Before they go into the safe, I put them in those shorty non-slip socks you get at the hospital and tie a knot in it.
Instead of oiling the blades, I use Marine Tuf-Cloth.

None are stored in the sheath, most are out on display on top of a low book case. I do keep one in carboard sheath, it gets lots of use and the cardboard makes for a safer carry.

I put two coats of Dyna Tek Gun Shield on my nice blades with couple hours of drying time in between coats\, followed by a light coating of Corrosion X and store in sheath in gun safe.

I put one coating of Gun Shield on my brass that is stored in a leather cartridge holder and it seems to work through hunting season. I use a cue tip and stay away from the primer!

Coat your steel magazines with Gun Shield and they are like slippery eels coming in and out of a pistol.

Check out Lucas Forge website. Windy River is the best product ever.

I don't store in sheaths either. I wipe down every six months to year with mineral oil and store on rubber coated racks or plastic (not air tight) boxes on shelves in humidity controlled safe. I use mineral oil with idea that might use blade for food preparation at some point. Really should use Renaissance wax on those that won't actually use.

+1

If you are on an extended hunting trip, leave your knife in its sheath. Grease or wax on brass hilts protects against ambergris chemical reaction.
In AK or Canada or lower 48 bear country. stick it in the ground or next to your sleeping bag.
A wrist thong helps if Mr. Grizzly gets too close or your gun runs dry. A knife does not require reloading....

I never store in sheaths. Bill’s Cases only. I use RIG grease per Burt Foster’s recommendation for my carbon and Damascus blades.

I’ve never used that rig. Do you wipe it on then then wipe it back off? Or leave it wet.

Wrap blades in S&W VCI paper. Store in AG Russell long zippered padded cases. 4 knives to each case. 2×2, opposed.

I use the 4 × 16 in..

https://agrussell.com/knife/Nylon-Zipper-Case-3-IN-X-10-IN--CZN-C310

Rick I wipe it on, leave a thin coat. It takes a very long time to dry out. I used it for years to grease o/u shotgun action internals.

Loose in lockable roll-away tool box drawers. More Renaissance wax than anything else although I do have Rig and other products for dead storage. Ivory and stag and formerly stacked leather get a little more attention than Micarta. I have zipper cases and sheathes in the same tool boxes for transportation and carry but I store blades loose coated on liners in a lockable case. I use a bunch of lockable tool boxes mostly Sears or Harbor Freight for things I consider attractive nuisances and not to be handled in my absence. Then again most any knife I would use in the field is liable to be in a knife block in the kitchen for regular use because why not if I enjoy using it.