:Updated links:

How to Get Rid of Rust
http://www.getridofthings.com/get-rid-of-rust.htm

How to Get Rid of Rust Stains
http://www.getridofthings.com/getridofruststains.htm

28 Practical Uses for Vinegar, Nature's Magic Cleanser
http://www.frugalfun.com/vinegar.html

How to Get Rid of Rust in Motorcycle Gas Tanks
http://thekneeslider.com/archives/2008/10/21/how-to-get-rid-of-rust-in-motorcycle-gas-tanks/