a while back I asked about the best products for cleaning seat upholstery, as I had a new to me jump seat that was in need of a good scrubbing.  I have now cleaned it and it looks new, though it really was filthy, with just the grime of use, plus some spots of greasy looking material.  I used washing soda and borax for pretreatment, followed by dishwashing soap and water, then vinegar rinse.  Beautiful results.
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David McNeely