It depends on what you're washing or why you need to wash it. I have just used hot water for cleaning up feces (eww). If you need to sterilize something, you can use a bleach/water mixture. Just make sure it's rinsed and dried before it comes into contact with your gecko.
Bleach and water solution to clean tanks. Spray down with alcohol and water to kill anything the bleach missed.
If a major "Poop & Smear Campaign" has taken place, the snake gets a bath with Johnson's Baby Shampoo.
(Don't own any geckos yet, so this probably didn't help at all)
I put tubs through a rinse cycle in the dishwasher, that's good hot water and they come out smelling clean. You don't want to dry them in there though, the buggers sometimes loose their shape. grrr, did that to my first set :main_thumbsdown:
yea make sure you rinse well when using chemicals and id suggest not soaking stuff. clean with it but if you soak some items such as the magnet rocks leak liquid inside that doesnt dry or can still hold vapor. i prefer dishsoap personally bleach scares the crap outta me.