"Yep, those durn wall warts are a-spreadin' like varmints."

I have 30+ ??, I guess. I started using a Sharpie too (especially for any that had odd connectors or were for sensitive computer-type electronic devices like PDAs). Or, I take a stick-on label, fold it over the wire near the barrel connector, and write the specs and device on it. I have hundreds of stickies left from diskettes (remember those?).

But for things like rechargeable lights etc., I use a carbide-tipped engraver (shaped like a Bic pen) and scratch the required volts and current ON THE DEVICE TO BE CHARGED. Scribe it right into the plastic, next to the connector. Any charger with specs that are appropriate will work. And the barrel connectors are very often the same size.

As to polarity: it's been a great many years (15+) since I saw any power supply that wasn't centre positive, outer negative. The last in my experience was a Korg Poly800 analog synthesizer that I had for a long, long time (welcome to the '80s, dude, and rock on!). I snipped and stripped the wires on a compatible adapter, slid on two layers of heat-shrink tubing, applied a dollop of solder, confirmed polarity with a multimeter, Bic'd the tubing, and attached a big sticky: "reversed polarity, do not use, except for korg poly 800."

This whole business is why I travel with a cheap multimeter and a high-watt-rated rheostat. I can create any charger I need out of the raw material in the junk drawer of any house in North America.