Balsa USA recommends sealing with polyurethane. What Campy says is very true about letting residue remain when using MinWax Polycrylic. However, if you want to spend the bucks and get a gallon ($42.00 at Lowes) of Varathane Diamond Floor Finsish (water based ploy-u) it will stand up much better than the MinWax. Comes in gloss, flat and satin. I have a wood fuel carrier finished with this stuff. Been using it for 3 years and it is exposed to RAW 15% and I have had zero problems with the finish.

It's what I use and it works for me.

Dan