I use soap and water and friction (rubbing my hands together)!!
Also, if the snake has laid in their own pee, I just let the water run tepid and gently wash the snake off- water only, no soap
Let your mom know that my grandchildren handle the snakes after they wash their hands and when they are finished with the snake they wash up again. All the grandkids are fine and have never been ill.
Honestly, I think we have more to fear from our own food supply.....