Our 1968 dredge manual was pretty spot on, unlike what henryt18 says.

Yeah that shellac trick works most of the time. But Betty's got a real point about the damp air. I had a dresser turn sticky even with a barrier coat because my basement was too humid. The old finish was basically sealed in moisture. Now I run a dehumidifier for a day before I even start. If the room feels wet, nothing will stick right.

Ugh, my friend's PR firm gave her that exact script.