Restoring your purchase
On any Mac with the same Apple Account, choose Cachet › Restore Purchase….
One purchase unlocks cleaning on every Mac you use with the same Apple Account.
On another Mac, or after reinstalling, choose Cachet › Restore Purchase…. Cachet tells you when it's unlocked.
If Cachet says no purchase was found, check that the App Store is signed in with the Apple Account you bought with, then try again. If it still doesn't unlock, contact us.