My suggestion is to wash the heck out of it with tap water first. Starting with RO/DI water is excessive since the first things you're going to wash out of it are the salts that dried in the sand and debris from the time in your aquarium.
Even tap water drying in your sand will leave less behind than your old aquarium water, the sand critters that died, detritus from previous life, etc.
I would, however, definitely follow it with a thorough RO/DI rinse.
Paul