I try and implement "universal precautions" whenever I handle any of my snakes. Even the established ones.
I do not give new snakes old tubs. Plastic is porous... every snake gets a new tub. Their names get written on in permanent sharpie.
If I am being really facidiuos... I sterilize anywhere hands go... door knobs, faucets, etc.
I also take dirty water dishes out with one hand, and put the clean ones in with the other (to avoid cross-contamination).
Just a few things to add.