Several years ago I ran accross an article regarding turpentine, the gest of which was that it has one property that other solvents don't have: it does not totally flash off and chemically bonds with the resins present in the finish. I am not a chemist so I can't vouch for the accuracy of this information nor can I explain why that is a good feature. That said, when I am using a combination of BLO/tung/varnish as a wiping finish I add turp as my thining agent. So far the results have been excellent.