Quote Originally Posted by Airsporter1st View Post
Does it not soak into leather then?

That's a rhetorical question, by the way, to which the answer is 'yes, Ballistol does soak into leather and keeps it supple' - just what is needed for piston washers.
it does indeed soak in just like any other emoilient but it acts as a barrier repelling further loading.
With a leather piston washer we need continual wetting of the leather.
It might be fine and difficult to notice any difference but ultimately you may not be able to resoak the inner material of the leather.