Advice Needed - Cleaning And Preservation Of An Aluminum Token

Warm water swish in a plastic cup, pat dry with cottony fabric.

I would not recommend using soap on aluminium coins; aluminium is one of the few metals that readily corrodes in both acidic and alkaline solutions, and "soap" is normally alkaline. In my younger days I have personally ruined several potentially-nice aluminium coins by cleaning them with bath soap. If you think to need to use a surfactant on an aluminium coin, make sure it's a pH-neutral soap. Personally, I'd use an organic solvent like ethanol or acetone instead; that should take off any adhered soil particles but leave the metal and its precious oxide later alone.

Jut looking at this piece, I would tend to assume none of it is actual dirt, but all of it is corrosion; aluminium can turn brown when it reacts with humic acids in soil, so I assume this was a metal detector find or it otherwise spent some time in the ground.

As for preservation, your best bet is to keep it dry. Aluminium has excellent corrosion resistance in dry air; raw aluminium metal when exposed to air rapidly forms a transparent aluminium oxide layer that protects the metal from further corrosion. It's only when moisture enters the equation that problems start because water, and things dissolved in that water, can disrupt the oxide layer.

Oh, and keep it away from other metals; don't just toss it in a jar with a bunch of other coins. Especially tarnished silver. I have also ruined a very nice aluminium medal by putting a heavily tarnished silver coin on top of it and letting it sit there for several months in a warm, humid environment. You know that trick of using a piece of aluminium foil and some baking soda to remove silver tarnish? Yeah, my scenario did much the same thing; I now have a silver coin that's nice and clean (on one side only), and a giant corrosion pit in my medal.

So in putting it in a 2x2, you've already done all you really need to do to preserve it from future damage.

I haven't done anything with it yet. Acetone will be my first approach. Would VerdiCare be of use on it?
Many thanks!