This might be one of the more ignorant things I've heard. If you can't disassemble a Marlin 336 for cleaning, you shouldn't be shooting a firearm at all. It's LITERALLY one screw. If you can open a door, you can disassemble a Marlin 336. It's not like we're taking for granted that I can build an AR-15 blindfolded because I've done it for years, it's an easier skill than changing your oil.

The one thing I haven't seen anyone suggest is a break in procedure. If these are new guns, then you'd benefit yourself by breaking the barrels in. Maybe it won't make a lot of difference in accuracy, but YES, it will make a difference in how easy they are to clean from now on. The better you break them in, the easier they'll be to clean.

Clean the bore after every shot for 10 rounds or more, then clean after every group (3-5rnds) for the next 10groups or more. Some guns I'm very careful to clean after every round for 100rnds, but if I'm lazy (like for a hunting rifle or a plinker), the above is what I do. Lower pressure rounds (like a 30-30), I would recommend actually a LONGER break in period.