Is it normal to preserve animals in jars?

I mostly have amphibians--salamanders, frogs, and toads. I have a few crawdads and insects. When I was 12 or 13, I began killing things and putting them in jars, the whole thing just seemed really fascinating to me. I would get a cigg lighter and put a rubber band around the bottom of it and the gas button and put the live specimen in the same container. After 10-15 mins, I'd take the freshly killed specimen out and preserve it in isopropyl rubbing alcohol (between 70 % and 91%). At this point, I probably have around 12 vertebrates an 20 invertebrates. So, fast forward to today, I'm 20 and I still do this. Rather than use butane gas, I simply kill them by dropping them straight into the jar of alcohol (if they're alive when they die, it gets into their lungs, thus better preserving them). About 4 years ago I quit feeling guilty about it.
P.S. I give them cute names like Leapy (a frog), Mordred (a crawdad), Godzilla (a large red black spotted red salamander), Shelly (a Madagascar hissing cockroach) and Kermit the Toad.