I clean them as I would any other silverware (soap and water) and then wipe them out with an alcohol prep pad. I really don't think boiling anything is necessary.
I use a blowtorch to blast mine for about 20 seconds and then let it cool down. Obviously I heat it up from under-neath. Doesn't take long and is sure to kill everything living on the spoon. All the other methods would work great too, I just like using the torch