I have to use Plug & Feather Lubricant - 1/2 pint can $25.00/ ea. when I use my Darda rock splitter. I apply it every 2 uses. So I use a can every 2 days. I did some snooping and figured out what this mystery lubricant was. And I found out it is Castrol optimol paste white t. I special ordered a 5 gal pail for a couple hundred bucks so I am set for a little while. Just wondering if there is an alternate lubricant that can also work the same.