I made a set of garden tools to give as a gift last year and due to time constraints only had time to put one coat of tung oil on the handles (purpleheart) before gifting them. I intended to get them back later and apply 2 or 3 more coats and then buff them but it never happened. I have them back to apply some more finish after a year of use, but being garden tools they have a thin layer of dirt and dust on them. I'm not sure how to go about cleaning off the grime before applying more oil. I had thought about just applying more oil and wiping them clean but I wasn't sure if this would seal any dirt in there. Can anyone offer some suggestions?