Wash the tracks in mild dish washing soapy water. Rinse very well. After the tracks dry I would suggest spraying the the track with auto primer and let dry. Then paint the tracks a dark brown color. then dry brush the tracks a metallic  silver color. I also apply a wash of reddish rust color unlessI am covering the tracks with "mud".

would promer make them too stiff to work with. i never thought of doing that. i just wash mine with matallic gray followede by black and dark rust, either washes or powders/pastels. after that i highlight the wear oarts with toned down silver. OTOH now i do mostly warwheels the tires of which can have theri own issues.

Not all vinyl tracks are made equal.

For example, Tamiya make two types of vinyl tracks.

1: The "old style" vinyl tracks which had to be melted together using the "hot screwdriver" method. These are more or less impervious to most hobby paints and solvents. These are a lighter metallic grey colour and are often loose in the box when you open the kit.

2: The later glueable/paintable tracks which can be glued and painted more easily. Be aware that there have been reports over the years that these have had a tendency to disintegrate after a period of time after being painted with enamel paints or after being given enamel based washes. It's recommended to use acrylic based paints for these tracks. These are a dark grey/almost black colour and often come as pairs joined by a sprue-like tree - they are also somewhat stiffer than the "regular" vinyl tracks used in earlier kits.

Here is a post that should give you all you need to know about finishing tracks.

www.armorama.com/modules.php

I'd say to install the tracks before painting them. I've always had problems painting vinyl tracks and then seeing the paint flake off as I try to flex them around the wheels.

I paint them overall burnt umber, paint any rubber pads nato black, wash with dirt colors or apply mud. There is no rust on active duty vehicles.

Gotta disagree with ya there cb1. Unless you are active in a desert environment that sandblasting your tracks clean every day there will be rust. Except when I was in Ft. Irwin I never saw a tracked vehicle that didn't have rusted track on some level.

I always use 'Rubber Bumper Paint' as primer. You can find it an auto parts store in a spray can. It's designed for rubber so it's got plenty of flex to it, haven't had any real problems with the top coat flaking off it yet.

Coldsteel6d

Gotta disagree with ya there cb1. Unless you are active in a desert environment that sandblasting your tracks clean every day there will be rust. Except when I was in Ft. Irwin I never saw a tracked vehicle that didn't have rusted track on some level.

That's ok, I can attest to my time at Ft Hood where we deployed every other week to the field from Jan85 to Dec 85 and I can assure you that we didn't have any rust. In Germany on the other hand, when the vehicles sat in the motor pool for weeks between training there was light rust, but nothing like some people paint their tracks with. Some of the kit tracks I have seen look worse than the vehicles sitting at the old Aberdeen armor museum for decades.

I also went to NTC in July/August 1985 and those tracks looked better than new after we came back to Ft Hood. 

Based on my experience driving and gunning on a Bradley, I still stand by my opinion. active duty vehicles that are deployed do not have rusty tracks. At lease not enough to notice at 1/35 scale.  

I think the rust was more a color of the metal, like a manhole cover on a city street. Is it rust colored, yes. Is it rusty, not really. And yes, I spent three years in Germany, four at Hood, three NTC rotations and another downrange, all on tanks, Brads and 113s. The only really rusty tracks I had were on the training vehicles I owned when I commanded a maintenance school at Fort Devens, Mass. But those vehicles sat in the motor pool, only moved into the bays when they were being trained on and were subjected to sun, snow, rain, ice of the New England weather.