To ensure a good bond for ground points on any metal surface in the car,
proceed as follows:
1) Clean the area around the bolt hole down to bright, shiny metal. An
easy of doing this is to use a pilot bonding end brush in a drill to
clean around the hole (see below for where to get these brushes). If a
brush is not available, scrape all paint off of the metal around the
hole and then use sandpaper to get a perfectly clean surface.
2) Once the surface is cleaned down to bright, shiny metal, coat the
surface well with any conductive, anti-corrosion surface compound, such
as Kopr-Shield (see below for where to get Kopr-Shield).
Pilot bonding end brushes are available from MSC Industrial Supply Co.
(Web site http://www.mscdirect.com)
1/2 End Brush with 3/16 pilot - P/N 00126722
1/2 End Brush with 1/4 pilot - P/N 00126730
Kopr-Shield Thomas & Betts P/N 201-31879 is available from The
Eastwood Co (web site
http://www.eastwoodco.com). It is also available at electrical
supply outlets such as CED or Stussers and is probably available at
Lowes and Home Depot.