@tubetime - the sticky stuff is likely some type of plasticiser which has migrated to the surface over time. Note that many older plasticisers are no longer considered safe to use. Depending on the situation, I've dusted the surface with corn starch, rubbed it in a bit and vacuumed or just brushed it off. You have to make the call whether a liquid solvent or a fine powder can do more damage to the surroundings in your particular situation ;-)