My son drove thru the mountains this weekend & was kind enough to bring me some nice river rocks to use in my tanks! I am wondering how to sterilize them? I have boiled them for awhile. Anything else?

well, once you boiled them, they should be fine

Yeah, multiple boiling should be sufficient. Go through them and toss out any stones you're not quite sure about (very deep crevices which may be hard to clean, rather than the usual nice smooth river stone). River rocks/stones are usually fine water chemistry wise, although personally what I do with any new stones is put them in a bucket of water, check the base line Ph/Gh/Kh or at least the Ph and then check it again in few days time after they've been soaking, just to be sure they're fine

I'd soak them in a 1:10 bleach/water solution for 24 hours, then boil them for at least 10 mins, and then put them in the sun to dry for at least a full day. Then I'd boil them again.

But I have been known to be overly fastidious...

Dave