I use DMSO to get magnesium and B12 into me as follows:

For magnesium: I bought magnesium chloride flakes. I take a dropper bottle and put some flakes in it, fill up with 99% DMSO. I let the flakes dissolve. There's always flakes left on the bottom so I know I've dissolved as much as I can. Then I put drops on my forearm and spread these out with my other forearm. It takes a few minutes to completely absorb.

For B12: I put 100 of 1000 mcg B12 lozenges into a 100 ml dark glass container and fill up with DMSO. It takes a while ( a week?) until these are broken down and dissolved. The unsolvable residue at the bottom/top: don't use that. The liquid you're left with is red (B12 is red) and thickish. Use as the magnesium solution. This gives you 1000 mcg B12 per 1 ml solution.

I have low stomach acidity from years of Iodine deficiency, so that's why I do it this way.

Be careful with DMSO: it dissolves everything including things you don't want it to dissolve: if you rest your DMSO infused arms on a painted table, the paint will be absorbed as well! Always make sure your arms are clean before applying. And when the DMSO is absorbed, quickly rince your arms with water. Only then put a shirt with sleeves on.