Brasso, and the similar for cleaning silver, copper, etc is for removing oxides from the non-ferrous metals… Or the auto polish…
or you can use just about any acid to help remove chrome oxide… soft drink contains acid , but it takes more work and you want something with grit (like toothpast, or polish) to help polish the chrome.
The part is cast bronze which has been nickel and maybe chrome plated. The green is how brass/bronze/copper oxidizes. Soaking in a vinegar soaked rag and scrubbing with a toothbrush/toothpaste will brighten it up.
The green is where the silver-colored chrome plating has been destroyed completely and the underlying brass/copper metal has been exposed to air/water and is now itself corroded.
The small black dots are where the chrome plating is mostly destroyed and the underlying metal is almost exposed. The failing chrome plating oxidises to a soft black material.
You’re not going to restore that part to anything even remotely good looking by just hand polishing it; you’re just going to make it look more scabrous.
An alternative might be to remove it from the wall as suggested above, polish the crap out of it on a buffing wheel until all the deteriorated chrome is removed, then paint it plain white or a similar color using either spray enamel or plain old latex wall paint. The spray enamel will be glossier, but the wall paint will better disguise the fact that the surface is now all cratered rather than smooth.
Or, for $3 apiece, go buy some new ones at Home Depot.
as has been said. the best way to make that glass hanger/holder clip look new again is to replace it. pieces that small are really really hard to hold against a buffer wheel and likely to be destroyed in the process anyway.
You can try Chrome Polish from an auto parts store. It won’t make it perfect, but it will look lots better. Chances are the plating is nickel over brass. The chrome polish will remove the verdigris for a while, but since the plating has been breached, it will return. Chrome polish is also good on shiny kitchen stuff like toasters, oven trim, and faucets.
Slight nitpick, you can’t brass plate (at least, not electroplate) anything. Electroplating occurs on the atomic level and brass is an alloy (mixture) of copper and zinc.
Most iron and steel items that are given a quality chrome plating are first copper plated (because copper plates easily onto iron), then nickel plated, to give the silver color, and finally chrome plated. The chrome layer is very thin and, for all intents and purposes, transparent. It is there just to protect the nickel layer.
The chrome layer is very hard and forms a chrome oxide layer that is very corrosion resistant to both acidic and basic solutions. Chlorine, however, will disrupt the chrome oxide, resulting in pinholes, which will allow the underlying layers to oxidize. Nickel turns black and copper turns green.
Unfortunately, most bathroom cleansers contain chlorine.
The easiest way to fix it is to replace it, as has been mentioned.
it depends on the specific process; I was on the floor of an auto parts supplier, and one of the things they made were bumpers for pickup trucks. Their plating process just used 5 or 6 stages of nickel plating prior to the final bright chrome.
Yep - the most common process deletes the copper (it’s expensive and doesn’t show).
The nickle will kinda sorta bond to steel, so good enough for parts not designed to last.
As it was explained to me (context: restoring 30’s era cars), the copper bonds to both steel and nickle. Nickle bonds much better to copper than to steel.
The old cars (pre-WWII) were thought of as major appliances - would last at least 20 years (if maintained, and they required TONS of nickle-and-dime maintenance).
To properly re-plate the bumpers, you used three-step plating.