Well from my reserach and from what ive been the best way is to use a gravel vacuum, and im planning on buying one tomorrow for my tank Just wait till the more knowledgable get online! Good luck my friend
Oh sorry mate, my mistake. Misread your post Missed the bit that says "new" lol I washed mine in tap water pretty well, basicaly all i did was load up a bunch of gravel into a bowl (rocks were to small for a sifting thing) fill it with water, hold my hand there and pour the dirty water out. Then repeat this until the water runs clear. Dont forget to mix the gravel around to ensure all the gravel is being cleaned.
I Have set 2 tanks up with Gravel. I washed in warm water, get your hands in flower, give it a good stir, used the wifes washing up bowl, then I put mine through a culinder. Job Done.