Bleaching 35mm Contact Sheets

[Hal]

Now that my darkroom is finally up and running, I thought the first thing I ought to do would be to make contacts of all my films so I could decide what was worth enlarging and what wasn't; the problem is that, after making a series of test exposures, I foolishly judged the print under the same midsummer sunlight that had been used to dry it, meaning my first batch of contacts are grey-to-black only, except under very strong light.

As the local photo shop is selling Tetenal Farmer's Reducer extremely cheap, could I use this to pull a useful amount of info from the contact sheet, or would it bleach all areas equally, thus keeping the same contrast? If possible, I'd prefer not to have to print the whole batch again.