Magnets
Today, more is known about the health-promoting effects of magnets (although not widely enough, in my opinion). In Japan, magnets are used for cheap and safe pain relief of sprains, bruises and sore muscles with no side-effects, the only contra-indication being a pace maker.
I use magnets mainly in the treatment of scars and, similar to intradermal needles, with the meridian system. The small, round magnets are attached to the skin on plasters and are usually left in place for 3-5 days for ongoing, gentle stimulation.