how to get that dull look?

I just watched that whole video, and I must say, that was a complete waste of money to get that tank and fender chromed, just to take the shine off.

I have sanded bare metal Sporty tanks and achieved the same "look" for the cost of sandpaper and about 3 hours of labor. You can go as far as you want with the different grits and get a chrome looking tank. Hit it with some Gibbs and protect it from rust without getting the yellow tint from clearing it.

If you figgure the cost of chrome plating that tank and fender VS the cost of about 8 grits of sandpaper and 3 hours for the same end result, that's just crazy to have it plated in the first place.

I did a regular metal gas tank for a friend in about 4 hours and it looked like chrome when I was done. He didn't have any Gibbs at the time, and when caught in the rain it surface rusted. It took about 20 minutes to go over it with 2000 grit, polish it, and spray it down with Gibbs, and it was chrome looking again, with no more surface rusting.

You can stop when you get the desired look out of the sandpaper, and simply smooth the surface if you don't want to get that shiny.

Sixball

A couple of people here saying muriatic acid doesn't work. This is like saying a welder doesn't work very well because their gas tank had pin holes in it.

First, stripping the chrome of a part with muriatic acid is not supposed to provide a finished shiny surface. It's only the first step. An aluminum part will appear blackened or golden anywhere nickel is left. If there's nickel left, it's very soft, and easily removed by machine wheel buffing.

The point of using acid, is that the chrome is an extremely hard surface that eats sandpaper, it comes off in tiny little flakes that scratch the underlying surface, and you'll spend a very long time trying to eradicate it from nooks and crannies.

Second, gasket surfaces and machined parts need to be protected, or removed. I use acrylic lacquer to coat areas I don't want eaten into.

Using muriatic acid and disposing of it properly is a PIA, but I have found it to be far less so than trying to sand chrome off. I have taken parts, immersed them for less than one minute, and watched the chrome foam off down to the nickel, and then removed the soft nickel in just 5 or 10 minutes on a buffing machine with coarse compound. Without the acid dip, I'd have been sanding for HOURS, gone through 20 bucks worth of abrasives, and have chrome flakes everywhere. This is about working smart, not hard.

Don't blame the tool if you think something "doesn't work". Professionals remove chrome plating with acid, not sand paper, and as with any other process, there's a good reason for it.

Probably the BEST advice for someone who doesn't want their chrome rocker boxes anymore, is to just buy some bare aluminum ones on ebay. They're cheap, and time is money or time that's far better spent on something else.