I just put together my first planted aquarium and used Flourite. I read lots of stories about it making a mess unless it was thoroughly rinsed, and the method I used resulted in perfectly clean substrate. It's clean enough that I can move the substrate around and nothing happens to the water. It's basically the same method gold panners use to classify their materials.
I used three 5 gallon buckets, but any containers would do. I dumped one bag at a time into a 5 gallon bucket & mixed it around with my hands, then poured the dirty water off. I did this a couple of times, which removed most of the fine particles. I completely filled a second 5 gallon bucket with water, then scooped a cupful at a time of the Flourite into a wire kitchen strainer (no idea about the mesh size), shook it around in the water, then dumped the clean Flourite into the third bucket. The sand sized particles went through the strainer, leaving the larger stuff rinsed and clean. I did refill the second bucket after the first bag.
I wound up with a couple of pounds of sand sized particles in the second bucket and strained that even further with a finer mesh wire screen. I only did this as there was still some finer stuff mixed in that looked like mud and I thought I might use the sand in a small aquarium. The sand came out perfectly clean, as well.
There are lots of videos on Youtube of gold panners classifying their dirt, and that'll give you a good idea of what I did. It took about an hour to clean two 15 pound bags.