Bleach. Kills bugs dead.
Take bleach, dilute it to a 10% bleach and 90% water mix and spray it on the glass tank (empty of course). Let it stand for about 30 minutes then take it out back and rinse it off with the garden hose or in your bathtub/shower if the outdoors creep you out.
After that let it dry or towel dry it and you should be good to go. If there are hard water stains on the glass you can use a diluted vinegar solution to spray on and wipe off. Should take off the stains. For stubborn stains, a razor blade works wonders.
I would HIGHLY recommend tossing all the decor that might have came with it or either run it through a sanitize mode in your dishwasher or boil it if they can be. For wood you can bake it at 200 degrees for an hour to kill things off.
The last thing you want is contaminated organisms to invade your snake. Treat everything used you get as infested and you will never have a problem.