You have a potential problem with trying to clean it with anything - it could cause a water spot.

My advice is to choose a small area in the back near the bottom where no one will notice. Take a clean white washcloth and wet it with warm water. Squeeze out most of the water and rub that small hidden area. Wait a few hours to see if there is a water spot - if there is, just stop right then and take the chair to a professional upholstery cleaner.

If there is no water spot, then try cleaning the arms. This time use a woolite or dish cleaner in a weak warm water solution. Do not over wet the arm. Rinse the arm with the wash cloth in clean water and let it dry. It will look terrible when it is wet, but should dry to look fine.

By the way - if you decide to just machine wash the seat make sure you put it back on the chair while it is wet - don't let it dry. When it is wet, it will dry into the correct form and not shrink. All slip covers should be put on wet from the washing machine - I learned that 50 years ago.

Good luck

Hi - have you looked @ foaming upholstery cleaners? The foam helps lift out soil & I think some can be vacuumed out after drying.

If that's not an option, you can make your own foam w/ detergent/soaps & use it almost the same way.

& DIYnetwork.com has lots of info on cleaning upholstery....

Here is a link that might be useful: search results @ DIY

Thanks very much to both of you. Very helpful advice. :)