Most glass toys should be perfectly safe to boil. Particularly borosilicate glass.

The only things you want to watch for are uneven heating (just like Pyrex) and avoiding sudden temperature shifts (ie. don't go from boiling to ice water).

As a sidenote, be gentle with glass as a strapon dildo, it's way less flexible/forgiving to the receiver than silicone or similar materials. It's still a great material though and can be used, just carefully. less

Actually, Pyrex (borosilicate glass) is meant to go from oven to freezer but I'd still avoid very sudden temperature shifts. I never recommend microwaving glass because of the uneven heating...hot spots can cause pretty painful burns. I see absolutely no reason to boil glass though...a good washing in hot water with some soap is all you really need! less

I think it's a good idea. Especially if the glass is thick, internal stresses can develop from the temperature change, which could cause a crack.

I would not recommend freezer to oven, or any sudden temperature changes. Pyrex cookware is much thinner than a glass dildo, and the hot air of an oven transmits heat slower than liquids. Even though it might be a 400-degree oven, as you probably know from sticking your hand in to retrieve something, the air of an oven doesn't burn you very fast. However, put a 400-degree piece of glass in some ice or a puddle of water, and I would bet it cracks.

Glass dildos are also much thicker than cookware, so internal stresses could develop between inside and outside, leading to a crack. It's unlikely to happen at the low temperatures of boiling water, but you also never know if there is already a defect inside the glass that makes it more susceptible.

Another caution when boiling glass: wrap the glass in a dishtowel then place it into the water. This will cushion it from bouncing around in the pot, and will also provide a little insulation from the bottom of the pot, which may be hotter than boiling. less