Alan Cowen of Tucson has recently started packaging up Jewell Amber Oil, a rocker box grease that's much more like historical rocker box greases than modern greases. Jewell Amber Oil is a non-fluid oil that melts and coats rocker box parts and most importantly runs into the valve guides to keep them lubricated.

Alan is packaging and selling the grease in caulking gun tubes and standard grease gun cartridges. It looks very promising - contact Alan or read his site for specs and more details on how to purchase.