Welcome to Elektronauts @midwestfrequencies!
There’s a few things you could try, I suggest these from experience of having bought some funky second hand gear in the past.
Firstly you can give it a gentle wipe down with a slightly damp cloth followed by a dry cloth. You can also use glass cleaner (spray it on to a cloth first, not on to the machine) to wipe down the metal and the glass (I would caution against using glass cleaner on the rubber elements as different cleaners have different formulations and some might be corrosive). Glass cleaner is good at removing grime without rubbing off printed text or damaging the finish. You can also gently pull off the encoders to give them a wipe down. If there’s oily residue on the surface, this should pick it up.
Secondly you can try baking soda, it’s very good at absorbing odours. Put a load of baking soda into a container and then put the Digitone in the same container (you can put it on a plate or something so it’s not touching the baking soda). Leave that for a couple of days.
Thirdly, if all else fails, just leave it out of its box to air out, ideally near an open window (of course be careful not to leave it by an open window if it’s raining or freezing outside). It might take a couple of weeks but the smell should improve.
Hope that helps!