Boiling silicone/metal dildos = safe sharing without condoms?

The definition of sterile is the complete absence of microorganisms.

In which case, bleach is considered to kill 99% of microorganisms. Boiling will not kill all microorgansims, and may not kill all endotoxins or spores, meaning that in the strictest use of the word, your toy will not technically be considered sterile (although we frequenty use that term, its not completely true).

Being fluid bonded does not mean that you can't pass infections to each other. Each person has their own normal flora. Normal flora is the microorgasims (like yeast and bacteria) that live normally and healthily in our body in a symbiotic relationship. However, the microorganisms that are considered normal and do not cause infection in one person's body, may cause infection to another. Likewise, microorganisms that live, in say, a persons rectal tract can cause infection in that persons own body if they were transfered to the vagina. This is because normal flora is a delicate condition of its and your body's checks and balances that keep these microorganisms from overgrowing and causing infection.

Technical speak aside... all things considered and for what it is worth, these methods of killing microorgansims should leave your toys sanitary enough to use in multiple places by multiple people without the likelyhood of infection. I would consider them good enough for the health of myself and my partner.