Boil them in a pressure cooker for an hour, then soak them in strong bleach for a day, they should come out completely sterilized.
This was how my grandma, who used to work in a hospital, sterilize tools used in operation room.
Yeah, I know, it's just that my OCD tells me to buy new ones... LOL
LOL! That'd make it hard to go to the dentist or medical facility without bringing your own new tools for them to use.
I try not to think about that...
Here if the complete manual:
Immediately after use: Wash the equipment with soap, rinse the equipment under running water until clean. Do not reuse for the day.
At the end of the day: Boil the used equipment in water using a pressure cooker at 105 degrees Celsius for one hour. Allow the equipment to cool during the night wrapped in a few layers of clean tissue paper. (In hospital they used sterilized cloth for this, tissue paper is a good home replacement.) The tissue paper should be disposed of after use.
The second day: Submerge the boiled equipment in a strong bleach entirely for 24 hours.
The third day: Rinse the bleach off the equipment using distilled water. Store in a box covered in tissue paper. (ditto for the sterilized cloth above)
Immediately before use: Dip the end of the tool to be used in 75% ethanol.