I have used linseed oil to renew old cork. I first used Soft Scrub kitchen cleanser to remove most of the dirt and grime. Then some very fine sand paper (150 grit) on any rough areas or stubborn dirt.

I mixed the straight linseed oil 50/50 with mineral spirits to improve penetration and applied several light coats, drying at least 24 hours in between coats.

The cork has a great feel and the linseed oil brings out the hightlights in the cork grain.