Recently installed some casework and in a couple of places end grain is
exposed and the customer wants us to seal that. Both plywood and
particle board suck up coatings and I am curious what would work best
to seal those surfaces.

Years ago I saw some cabinets with their bases sealed with something
they called shellac with a lot of wax - does that make any sense - it
really sealed the wood.

Anybody got any suggestions?

Thanks