Run an orbital sander over the entire plywood floor to remove any roughness or splintering.
Remove sawdust using a shop vacuum.
Fill a paint tray with enough clear sealant for the bottom to be 2 inches thick.
Coat a long-handled paint roller into the sealant, then roll the sealant over the entire plywood flooring. Allow the sealant coating to dry for six hours.
Repeat this process two more times, allowing the sealant to dry for six hours in between each coat.