You don't really need to lubricate the threads exactly, although anti-seize is more appropriate. We ship them with a little bit of copper-colored anti-seize compound to help the initial thread break-in on the rifle. Normally once the suppressor is used initially on a rifle and installed/removed a half dozen times and 20 rounds, the threads are broken in and seated and no subsequent anti-seize is needed.
If you want use some of that, you can use automotive anti-seize similar to this
http://www.permatex.com/products/Au...ts/Permatex_Copper_Anti-Seize_Lubricant_b.htm
Just a tiny amount.
If you do put any on the threads, make sure no sand or dirt or grit gets stuck to the compound.