keeping it clean

Taking the bus back home from a trip into town, I found myself next to a fellow who, judging from the smell of things, was apparently coming straight from "work," in his Trash Pick-Up uniform. He also was a proudly dredlocked, colour-bearing Rastafarian. For the entirety of the 45-minute ride, he talked without seeming to stop for breath, lecturing us all on the woes of "the man," who gets nothing from the government, on the power of the people, and on the ways of the island.
As he talked about the island, a tourist behind us interjected to query our Rasta friend as to whether there was a drug problem here on the island.
Still without a pause for breath, Rasta jumped into this issue. "Oh yeah, man. Big problem. We got big problems. People here on the island, they just don't know what to do, so they do drugs. Big problem. Yeah man. Me, I don't do too much . . . "
At this point I looked at him and, wondering if I had heard him right, asked if he had just said "too much."
In the middle of his speech still, he didn't hear me and kept going. The bus driver, however, from the front, tossed back an affirmation that indeed, that's what he had said.
Tuning back in to Rasta Man, I caught the remainder of his explanation:
" . . . I don't do the cocaine. I don't smoke. I stick with the clean grass--straight from Jamaica. That's the good grass . . ."
I feel very informed now, I dare say, being ignorant before now about the merits and origins of "clean" grass.