It's not a silly question! When I first started, I used an alcohol wipe but then I'd read that it wasn't necessary. If you wash and thoroughly rinse and dry your hands, that should be fine in your own home. Of course in the lab, they will use alcohol because that's a different environment. I don't know about
the alcohol having an effect on the reading. It evaporates and I don't know if anything is left to affect the reading. One thing I always do and I'm really not sure it's necessary, I wipe the first bead of blood away with a tissue and test the second bead of blood. I thought I'd read it's better to do that but I can't remember where.