How do you save your gameplay if you are going to clear the cache of your browser?
Save to Disk. It will send your save game to your computer, then you can clear the cache and select Load from Disk to select the save file from your computer.
Even if i am using a phone?
Should work on a phone as well! If you're on iphone it'll save it to your files app, idk about android but it should work there too.