What is that hard, brown residue that forms near the hand brakes or handlebars of old bikes?

Question

I bought two old bicycles that have this very tough, brown, and almost moldy-looking crust that surrounds the base of the hand brakes. You can see a clearer picture here: http://www-hsc.usc.edu/~rpinder/images/ni6.jpg . Any idea what that is? And what is the best thing to use to clean it off (I've chipped most of it off)?

EDIT: Most of the answers indicate rust, but I still have my doubts. The substance is almost like dried-out caramel and has formed a very thick layer (up to 1/4 inch thick). Once I start digging at it, it comes off in one piece. It's not what I expect from rust, so can it be something else? Thanks!

Answer 1

<>It's rust. Get something called Naval Jelly which will take it off.
http://www.loctiteproducts.com/products/detail.asp?catid=13&subid=47&plid=169

PS: You could be right...thie picture doesn't do it justice. It could be old, dried-up grease. If so, break off what you can then soak the remainder in WD-40 or similar for a couple days...that should clean it.

Answer 2

The residue is most likely rust and grease that has collected dust. The rust is probably comming from underneath a fixture like grips or brake assembly.
Regards
Michael

Answer 3

It's your brakes son. Your pads are probably worn out looking at the age of it I'm not surprised. I replaced mine and work 100% better. Also check the rims for dirt a good car wax will solve this in a minute.

Answer 4

I don't see anything...I assume you know what rust is...so it's probably old sweat and body oils from all the people who held those grimey brakehoods

BTW...I hope you're 6'6" - CUZ THAT BIKE IS HUGE!!!

Answer 5

that is the iron oxide, popularly known as rust. keep you bike indoors, humidity or direct contact with water is the cause. as iron gets corroded in the presence of water. cover your bike when not in use.

Answer 6

rust