I would like to input my 2 cents and tell you:
The myth of lsd staying in your spinal cord is actually true.
However, practically every chemical you put in your body deposits trace amounts of itself into your spinal cord. Ask a chiropractor.
I had a former boss who had a back condition that required him to go to a chiropractor every 3 or 4 months. He told me the doc would do a special back stretching/cracking procedure on him (he described exactly what was done but I haven't talked to him in over a year so I can't remember the exact details), and afterward all of the toxins stored in his spinal cord were released (he was a heavy smoker), and his body felt so shitty that he could barely drive himself home, but he felt great a day or two later.
If anyone actually calls a chiropractor and finds out my former boss was full of shit let me know, but he was a very honest guy so I don't doubt him.
Oh yeah, now that I think about it, his back condition was called a 'stinger'.