Wont help you much but I did some hinge points on the weekend and didnt want to put grease or any oil on a plastic part. So I just cleaned the first large part of the hole that takes the knuckle with a cotton bud. 22 hinges and they all are very smooth. Another thing I did, was to rest the part being glued knuckle down so the excess epoxy pooled around the exposed base inside the wing. Looks very strong when looking inside the wing.