I'm not a chemist or anything, but I thought I might try my hand at improving upon the cheap aftershaves that I've purchased lately. I've tried this with Old Spice Classic and Aqua Velva, which I really like a lot. Some might say that I'm adding stuff already contained in the bottle, but I think these additions have improved their performance significantly.
I've used about 1/3 of each bottle. In each bottle, I've added Thayers unscented witch hazel (which hasn't altered the scent at all), and about 30 drops of vegetable glycerin. The scent hasn't been altered at all, but what has changed is how my skin feels after applying it. Irritation is cleared up very quickly, and it adds moisture to my skin. I really like the way my skin feels after using my concoctions.
These aren't original ideas by the way. I've read about adding witch hazel to aftershaves before, but glycerin just popped into my head somehow. Anyway, though I would share. They're cheap aftershaves and if you mess up, just throw them away and buy new stuff. But I don't think you can mess this up!
Cheap Aftershave Doctoring