This NEEDS to be in your toolbox. Liqui Moly Copper Anti-Seize compound is used for any bolts or nuts that must be removed later on. This is a must-have for lug bolts & nuts - put a small amount on the threads to prevent the bolt from rusting internally. Also good for suspension components.
This CANNOT be used on head bolts. If you were thinking of it, you REALLY shouldn't be working on your own car. (yes, this was done by someone)