RE Cheapest realistic looking gravel for rails

I was thinking of using regular sand for gravel on the rails since the size is very close to scale ie smaller than ones scale hand,. Here is what I would do First sift it to get all the rubbish out then wave a magnet over it too get any fillings etc, out , third put it in a salt - spice shaker after it has been washed and dried.
spray a mixture of white glue and isopropel alcohol on the sand when you place it on the rails. Spray paint with a light gray since this simulates oil grease etc comming off the cars on the gravel .

any suggestions to improve this readily welcome

We like ot use a mixture of things here, real rocks that we pick off the shoulder of the highway, and then we add in some things, just to make it look a little more real. but mainly just rock.