Rust proofing helps reduce the rate of rustication in iron and steel. Rust proofing is a form of preservation and protection. Rust proofing needs to periodically renew for long term effect. Rust proofing is particularly used for the automobile industry, where the frame (chassis) and its attachments must be rust proofed. Paint is the final part of rust proofing. Also, aftermarket kits are available to apply rust proofing compounds both to external surfaces and inside enclosed sections, for example sills/rocker panels through either existing or specially drilled holes.