I use the blue painters tape masking tape to remove the scales; I always worry the duct tape will stick to the skin where scales have already been removed and damage the skin somehow. I want to add the "lazy-man's/procrastinator's method" that I find myself using more and more often...because sometimes folks are pressed for time. I skin, scrape the fat, and tack about 1/2 the snakes I get as soon as I get them. Sometimes, especially when I'm trying to catch up on a lot of work around the house, I'll thaw out any snakes I've been given that are frozen or that I didn't have time to mess with and just threw in the freezer and when they are thawed, I'll cut them with scissors up the belly center, skin them, and then wrap the skin onto a stick that's about 5" longer than the skin is wide. I will stretch the skin out flat as I roll it as tightly as possible onto the stick and onto itself. Once on the stick, I wrap it with a paper towel and use a sharpie to lable the type and length and make any notes about the condition of the skin. Take that and stick it in a ziplock and throw it back in the freezer. I'll do this with fresh snakes too...any snakes if I do not have time to properly take them from snake to skin to tacked to dry in one go. When I need a skin, I just thaw one out, wash it with dawn, scrape the fat off, tack it up, let it dry out, then rehydrate with water and dawn again and rinse. I can't tell any difference between ones I take care of immediately and the ones I deal with after thawing back out.
As far as the one with odor...yup, you have to pick up a roadkill really soon after it's demise for it not to get to stinking pretty bad. I picked up a fairly fresh, super long, incredibly beautiful bull snake two summers ago...and it was RIPE! I had to give it a go, though, and it was all I could do to get it skinned, scraped, and tacked up without puking. I swallowed at least one fly and had others crawling on my face and trying to go up my nostrils as I worked. I gave it a good washing in dawn and warm water and actually poured some dead downwind detergent and scent killer into the mix. I then tacked it up and dried it. It still had some funkiness to it once it dried, so I washed it in dawn again, tacked it back up, and left it out in the sun for several days. It eventually did not smell anymore, and it backed a bow I made for my dad just fine and dandy. Unfortunately, my dad was showing it off to my uncle (probably had a couple of drinks together, as they don't see each other but once or twice a year) and he strung it backwards with a stringer and snapped the upper limb. While he destroyed the limb, the snakeskin stayed perfectly intact, so you can definitely get a great backing skin off a stinky snake if its not too far gone and you can stomach the process.