Materials eventually dissolved by methanol include aluminum, brass, calcium, copper, zinc, galvanized steel, magnesium, potassium, lead, rubber, Buna-n, shellac, varnish, Plexiglas, neoprene, Nitrile, plastics, and many paints

Acceptable (rated “good” for corrosion resistance) materials include bronze, carbon steel, cast iron, Monel, 302, 304, 316 & 416 stainless steel, and titanium.
Preferred material for seals are Viton and Flourel