Best Way to Convert battery-powered gadget to 110 V AC current?

You can buy various ac adapters at Radio Shack.  You will have to improvise on the wiring or add a jack internally.  You will need a 6 volt DC battery eliminator, I don't know what the amperage should but get one that has at least .5 amp if not more.

Why not purchase rechargeable batteries and a charger? Then you'll have the ability to charge batteries for all of your battery powered accessories/tools once you replace the batteries.

I prefer my paint mixer...it works great! Takes just seconds to mix.

One tool that multi-tasks!

My daughter gave me a nail polisher which used two AA batteries. I found an AC to DC adapter in a thrift shop for a buck. Just had to match up the voltage and made sure the amps were low. Wired the polisher directly to the adapter. Works great.

Jim

For what it will cost to convert that paint shaker or buy NIMH batteries for it you could just buy a Badger paint mixer and have a much better tool for mixing paint.

It's what I use. $10.