Does anyone out there have any recommendations on something to put on the rubber seals to keep them from drying out or refresh older seals that are already drying out a bit? I was thinking may be some sort of oil or lotion but I'm not sure so I thought I would pick the brains of the collective here.

Look for silicone grease for O-rings

20

Or even silcone spray might work, if you respray from time to time...

And worse comes to worse, strip out the seal and apply fresh silicon. I've done that with a couple of ammo cans.

food grade mineral oil might work, you can get it at the pharmacy. I dunno what you are storing in these cans so...I gave you the safest bet.

Maybe Armor All?

try lanolin or petroleum jelly

I used regular old white lithium grease. Apply lightly and it works fine.