Do you sterilize your toothbrush? How about forks and spoons? You got more cooties from the last person you kissed than you ever will from a razor. .
Well, no-one other than me has ever used my toothbrushes, and while forks and spoons have gone through my dishwasher, I think there is very little chance that they have ever had some person that I don't know's blood on them. The correct answer is that razors, and other things can only be sterilized with an autoclave which uses high pressure steam at about 275°F. Unfortunately they cost at least a couple of grand. What many people use is a hospital grade, EPA approved, broad spectrum disinfectant to sanitize items. Barbicide is the salon/barber shop/manicurist industry standard and is available as a concentrate for about $12 for a pint container that will last quite a long time. A 10 minute soak is recommended.
You'll probably continue to get snarky remarks unless you provide a little more detail on what you are trying to do. If you are talking about the handle of a cartridge razor, then scrub with dish soap in warm water and it should be fine. If you are talking about cartridges themselves, well they should already be sterile and ready to use.
Everyone has a different comfort level. I'm an admitted germophobe. I sanitize vintage razors by removing the visible crud with a tooth brush and Scrubbing Bubbles, dropping them in my heated ultrasonic cleaner to clean out the nooks and crannies, and then following up with a 10-minute Barbicide soak. I found this information to be handy: https://www.badgerandblade.com/forum/wiki/Safety_razor_maintenance Everyone stay away from @TobyC ... he has cooties.
I wouldn't exactly call myself a germophobe but I did have a career in risk management! I do pretty much the same as you do although I don't have an ultrasonic cleaner - maybe I should get one? I do a 15-20 minute soak in a dish soap solution, the scrubbing bubbles and old toothbrush thing, a rub with some metal polish and then the Barbicide soak.
Well then, there you go! I've never believed in sanitizing my own razors, either DEs, SEs, injectors or cartridges. If they're metal, they go through the dishwasher when I get them (always used), and they're good to go. New plastic carts? Good to go. Tried sanitizing a few times but figured what's the point and I ain't dead yet. Swishing them in 91% alcohol to remove water/prolong blade life is another matter.
I wouldn't suggest getting an ultrasonic cleaner for razors. If you need one for cleaning other things, though, this model has given me good service. https://www.harborfreight.com/25-liter-ultrasonic-cleaner-63256.html
Thanks. That one looks pretty good. I bet it would also do a good job on a pair of gummed up motorcycle carbs I have!