Rustproofing

Waxoyl, or Prolab. Waxoyl is designed for long life and Prolab is better for annual applications. 

Both products can be done DIY, or can be professionally applied. Both are no-drip, safe for both electric cars and ICE cars. Both are very safe for the environment and will perform exceptionally well at preventing rust.
More info on Waxoyl 
More info on Prolab