slight rust on the side of the links of my bike chain. I'm runing with dry lube which is teflon based I think. The rust isn't deep. Can I go at it with a brass bristle brush, or will that damage it and the orings?
I would use something like WD40, and a soft cloth to rub the rust away. Then apply the right amount of chain lubricant and you will be good to go. You can use a brass bristle brush, provided you do it gently like this guy in the video. A toothbrush will also work. This is light surface rust and IMHO nothing to worry about too much.
You can buy a special tool to clean the chain, it is normally circular/spiral shaped and you twist the brush as it runs along the length of the chain.
Also, you can purchase a special chain lube tool, that basically hugs the chain and has a hole to insert a straw.
I use a brass brush and kerosene on my chains (both bicycle and motorcycle). it works great and i have never had a problem. i have read that WD40 is inadvisable on o-ring chains, as it can displace the lubrication behind the o-rings. not sure how accurate that is. My neighbor cleans his chain with WD40, and it hasn't flown off the bike while running yet...