Occasionally I find early T lamps that were nickel plated. Usually the plating can be buffed or bead blasted off of brass castings. In the case of spinning or lamp tops, blasting will distort the parts and buffing will not get the plating from corners and can destroy the lettering.
I bought a product called B-929 nickel stripper from Metalx Specialty Products, Inc. they referred me to one of there dealers so could get there product in a small quantity. I bought a 2.5 lb bottle from Rodney Wilke , Ztecsol@gmail.com. As you can see, it works pretty well. You need to mix the powder in water and let it work 3-4 hours at 120-150 degrees. I mixed it in a stainless steel container and kept it warm in my BBQ. The nickel turns black and comes off pretty easy in a hydrogen peroxide and water solution. The nickel stripper was about $29.00 for the 2.5 lb bottle.
Don't throw your mix out. It will continue to strip nickel many, many times. Just add a little distilled water to make up for lost volume. Cool it and cap it as soon as you can.