You would need to remove any contaminants. The one I bought was dry. The brake fluid will act on the rubber seals in the pump and ruin it after a while anyhow.
During my short stint as a heavy equipment mechanic, we used a metal tank with a sealed lid with scrhader valve, a pressure gauge, a ring and hook on top. Pour in a quart of fluid, put the lid on, Hang it up, put 10-15 psi head pressure on it with compressed air.
One guy who did brakes all the time used regulated air into it and had a cutoff valve.
So you can go as simple or elaborate as you want. As they say, necessity is the mother of invention.