A thin sheet of plywood or a big piece of cardboard takes care of that if you are planning on storing canned goods on them. Or, leave the canned goods in their flats. The latter is what we do.
Amazon actually sells plastic liners that fit perfectly, or as mentioned leave em in the trays.
find a warehouse, or some place going through a remodel. maybe just maybe you can get some
of that orange warehouse "racking" the up-rights and the rails, the rails come in different lengths
and the up-rights, 8' and up. picked up a bunch where I was working years ago, can easily hold 2
pallets of sugar at that time was 42 bundles 50# each on bottom rails and 2 on top, pallets of
flour, beer, sodas, etc. the only thing that got them to flex (bow down a little) was stuff like sugar
basically the same as you see in Costco, Home Dept, Lowes, the heavy duty orange "racking" they
lock in place with tabs and a pin that keeps em from popping out, plus they are adjustable, they
also make great reloading benches, cut a piece of plywood and "drop" it right in the recesses on
the rails. Stack as much lead, bullets, brass and be done
-Snoopz