OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Four Stroke Lawn Mower Frames Cleaning up old mower wheels/tyres?

Hot tap water (not boiling) and dish washing detergent solution soaked for at least 10 minutes.
Then scrub with a plastic fibrous scourer ( the one you see on one side of most household sponges).
That's how I did a pair of old 1970s Victa wheels and it for a great deal of the dried up grime off ( but not all admittedly). It didn't harm the wheels at least.