Best plants for soil detox?

Recently I was talking with a commercial cannabis grower in our state (Colorado) and he told me that hemp and cannabis were great plants for detoxing the soil, but the first 2 or 3 years the crop had to be disposed of as toxic waste. That got me thinking, what other plants are good for soil detox and if they are detoxing the soil, wouldn't it be counterproductive to compost those plants? I am excited to see what we will learn once this certification class opens.