I had to rinse 500 lbs. of black sand so I went and bought a 100 gallon Rubbermaid tube to do it with.. just run the hose through all of it good and let the dirty water over flow out the top! Of course you have to do it outside but that is the best way I have found to do it and I did it with sand so I bet it would be a lot easier with gravel because it will not float up in the water like sand does!!!
This is what I've done with large amounts of gravel, although I used something more like 10-15 gallon bucket (industrial paint can size.) Use a blast setting on the hose and the debris will fly loose and float over the top. I did it in the summer so it wasn't unpleasant. For small amounts a small bucket, spigot and a hand works fine.
If the gravel is really clean, you'll be able to tell once you get some in a bucket, but it can be deceptively filthy if the sediment is finely layered and uniform.