Use any cleaning product sold in supermarkets and a brush with hard bristles, just as you would for cleaning a tiled floor. It is just as easy to clean a cork surface as tiles but some precautions should be taken.
Mix the cleaner with water in a bucket according to instructions on the package and start brushing. Wait a few minutes before repeating the operation. Then rinse carefully, to get rid of all traces of the cleaner.
Avoid additives. Too much sealant does create a protective film but this inhibits the cork’s anti-slip properties. Similarly, oils used for wood makes the cork slippery. So does detergent if it is not sufficiently rinced.