Removing the oxidation physically is probably the easiest way. I would skip the chemicals. HCl probably wouldnt protect your probe but actually convert a small amount of it to a metal salt and make a few hydrogen bubbles at the same time. Acetone shouldn't do anything the metal as far as removing oxides. But it would help clean anything else stuck to it. Then so would soap and water.

Just making sure the probe is clean and dry when you store it to help prevent oxidation is probably the best approach.

If you want to go a step beyond, storing it in contact with a sacrificial anode like they do boats would probably work.

Wiping it once or twice with steel wool seems easier to me.

The best thing to use to clean the probes on these is distilled water. Do not use anything that might cause future readings to be skewed, such as Hydrocloric Acid. A scrubby and distilled water should be all that is needed. Even your tap water could influence the readings you would get.

Thanks all!