I got about 75% of the way thru a plywood version of the Dutch Tool Chest. My plan was to paint the outside with milk paint and likely cover that paint with a home brew of MS/BLO/poly. My question is whether I should also coat the inside with the MS/BLO/poly mix, shellac, something else? Or should I leave it natural? I know some folks leave the inside unfinished - does using plywood change that?