Everybody is different in developing sensitivities. One time exposure can be enough. You mentioned washing your hands afterwards. Washing your hands with soap and water is not enough to remove all epoxy residue, as I know from my own experience. The last time I used epoxy I got lazy and only used soap and water after getting a small amount on my hands. An hour later I got the worst runny nose I ever had and it lasted for two weeks. Other times that I only used soap and water I got hives on my wrists, even though the epoxy was not on my wrists. For me, washing with naptha or ethanol has been good enough in the past, but I am really afraid to use epoxy unless I really need to for some kind of repair around the house. Some solvents carry the offending chemicals through your skin and into the blood, making everything worse. For example, when I was about 13 years old, I mixed epoxy with a plexiglass solvent (something like "methylene dichloride") intending to invent a new glue. My whole body turned red like a sunburn and my skin hurt so much that I was in agony from my clothes touching my skin. So, although I think it is safe to clean up with naptha or ethanol, I would be cautious of other solvents. I personally would not be able to use epoxy for other than a tiny repair. I would be afraid to use large areas such as pore filing or laminating, because I am just too sensitive.