Not really restricted to DIY but...
When I was a kid we used to buy a tub of gloop called Lion Ointment[1] for dressing wounds. It was particularly good for dealing with dirty wounds, or ones with fragments in like splinters, or gravel acquired while aquaplaning off one's bike across a new road surface etc. Slap some on, dress it, and a day or so later it would have drawn anything that should not have been in there out and into the dressing. It was very effective on septic wounds as well. Alas they no longer seem to make it, so what do people use these days as a drawing agent on a wound?
[1] A concoction of petroleum jelly, beeswax and various other things made by Burgess IIRC. It was golden in colour, a stiff "set honey" like viscosity, and with a distinctive aroma. We originally found out about it following a recommendation from a chap who had served in the trenches in WWI and found it ideal for drawing shrapnel fragments from wounds.