With no disrespect meant to anyone:
NO OIL
NO SEALANT
The oil over time will become hard causing the piston to stick.
The Brasso might be OK, have never tested it.
You can polish the piston using a 1500 grit wet or dry crocus cloth.
As for the sealant, if the surfaces are flat, no sealant is necessary. If the surfaces are not flat, use heat and pressure to straighten them (and then they will be flat and not leak).
Sealant will be broken down by the association with fuel, and will flow to the smallest part of the carburetor through which fuel flows (the idle tubes) and will clog them making a MUCH more difficult rebuild in a few weeks.
Jon.
