I did it in the last couple of days with no problem. I sharpened a popsicle stick to a point, made up a tiny bit of old, out-of-date Proseal on a little pallet, then used the stick to slather it onto the required area where the skin is bulged a bit by the overlap. I used the pointed end to try to push the Proseal into the gap. Then, I wiped the area off so that just the overlap area retained the Proseal. I also carefully used Acetone to clean the skins of Proseal. In one case, I reapplied because I visually saw that I hadn't pushed the Proseal into the gap well enough. It was very simple and easy.