Many different lubricants are recommended for rubbing out finishes with an abrasive. Here’s how they differ.
The more waxy or oily the lubricant the better it reduces scratching and sandpaper clogging but the slower it cuts. The more watery the lubricant the more aggressive the cutting but the more pronounced the scratches.
So wax is the most lubricating of the common lubricants suggested. Oil would be next, followed by a mixture of oil and mineral spirits.
On the more aggressive side, straight mineral spirits (paint thinner) still provides some lubrication while allowing the abrasive to cut effectively. Soapy water provides slightly more lubrication than straight water, which still provides enough to somewhat reduce sandpaper clogging.