Rewards can be claimed from the menu that opens up when clicked to wallet address on the website or mobile.
Rewards from races may appear on your claimable rewards after a race ends. It might take from 5 minutes to 12 hours.
Competitive races uses unclaimed reward tokens first to save users from extra transactions. If you enter a competitive race with a 50 Slime entry fee and if you have any unclaimed Slime balance, race entry fee is deducted from unclaimed reward balance first.