There is a chemical called "Metal Prep" which washes and nutralizes the rust..PPG DX520 is for galvanized or bare metal surfaces and
PPG DX579 is for aluminum surface prep.
http://www.tcpglobal.com/autobodydepot/rustremove.aspx
I use this solution to prepare all bare metal before sealer/primer.
Usually you mix 1 part solution and 5 parts water.
Be sure to wear gloves during application and not to splash any of it around, this stuff is highly corrosive.
Follow directions or PM me for pointers.
To wash all the grease off just use dish washing liquid detergent and a good ole brush before using metal prep chemicals.
If you paint without using bare metal prep you will see rust come back and bubbles form under the paint. It will also fall off once the rust starts.