TTJames,

The rust and previous contents are concerns to be aware of, not reasons to not do something.
I used to use an old Tide bottle. Loved its big bright red appearance for fuel.
Just cleaned it up really good.
As for rust, be aware of its possibility and periodically check for it before refueling the can.
These cans are usually coated on the inside. The coating varies with the intent of the original filler.
(I know this because used to work for an olive processor and packager.)
If you use an can previously designed for glow fuel it will be coated with a product that can handle the glow fuel
and reduce the risk of rust. It won't last forever but should give you a good life.

I prefer the metal can because the batter/pump fit on it better and it is more comfortable to carry.

Good Luck,
KW_Counter