rusty cassette

You may be able to salvage the cassette and chain with WD40 and a wire brush if the rust is just on the surface. If this works make sure to lubricate everything with light oil WD40 is not a good lubricant. If this fails to remove the rust then you are better off replacing both.

yeah Davereo is right !!!You may be able to salvage the cassette and chain with WD40 and a wire brush if the rust is just on the surface. If this works make sure to lubricate everything with light oil WD40 is not a good lubricant. If this fails to remove the rust then you are better off replacing both. this is a very good idea and i like it!!!

I cleaned up a rusty chain/casette on a used bike i picked up pretty well by using something called pb blaster from the hardware store.

BLASTER PB PENETRATING CATALYST 16-PB BLASTER CHEMICAL COMPANY

I just sprayed it on, let it sit for a few minutes then scrubbed the hek out of it and repeated that a couple times. Chain looks incredible now. Couldn't get the casette perfect but it looks much better now. I would just make sure you get the wd40/pb blaster off the chain/cassette before you apply any real lube.

Revds said:

I bought an abandoned Mountain Bike from an outdoor lodge this summer. The lodge was getting out of mountain biking and had left two sitting in their racks over the winter ( ! ). At $20 I saw that one of them had potential. I have started to clean it up and repair it. But the chain and cassette are covered with a thin layer of rust. Do I scrap them, or is there some way I can get the rust off?

Revds

you can buy a cassette for less than you paid for the bike.

Get some wd40 or something like it in a can, not spray and soak it for a day or two.
Then some hot, and I mean hot, soapy water with a good rinse and some proper
chain lube, I use 3n1, because I am cheap!

I think CRC 5-56 is a far better product than wd40!

CRC 5-56 from CRC

I bought a used bike with a slightly rusty chain, cogs looked fine. I just oiled it good
and after a few miles it was fine. I have cleaned and oiled it a couple times since
and it is working 100%,

Frankly on a $20 MTB I would just clean the chain moderately, oil it up and ride it. Any surface rust will wear off pretty quickly and once the cassette and chain are toast replace them. Chances are if they are really rusty they were probably well ridden and worn too much anyway and will soon have to be replaced for better performance.