Be very careful with DMSO (Dimenthyl Sulfoxide). As a chemist, I've used DMSO and it is a great compound because it is an EXTREMELY effective solvent.
The reason that the FDA is against DMSO for home use is because it basically dissolves almost anything and takes it along for the ride. Since it is readily absorbed into the skin, anything dissolved in it is also absorbed. This can be dangerous if you inadvertantly come in contact with a hazardous chemical while using DMSO. Many things that are safe when placed on the skin aren't necessarily so when they are absorbed into the body.
DMSO should be stored in glass containers (not plastic) and whatever area on the body it touches should be extremely clean. Be very conscious of not contaminating your bottle by dipping anything into it and make sure any container you use is also clean. As long as you're careful, you shouldn't have any problems.