WD-40 works real well on coins, should on this also. Spray enough into a small container to cover the coin/token and let set for 2 to 3 days. Wash with liquid soap and warm water using a tooth brush.
Unlike the brass tokens the aluminums truly deteriorate in harsh ground. You can make it readable but the deep pits are there to stay. You might try aluminum jelly if you can find any.
WD-40 won't take out the discoloration. I've had good results on stained white metal tokens
with GO-JO rubbing with a stick of wood.
Wd-40 is a fish oil bi-product, so when you use WD-40 you are soaking in animal oil. Some say vegetable oil is better on coins. You can use Oil or Walnut oil, etc. also. I will give the WD-40 a try though...PS if you've never tried it, spray WD-40 on your fishing bait before you through it in. Stinks like fish, to the fish. Really works!
ROSE MARIE BEAUTY SHOPPE / PHONE / 104 / SPENCER / W. VA. - see pic of one in somewhat better condition on Richard's Token Database - TokenCatalog.com
John in the Great 208