/diy/ - Do It Yourself

Haven't had to deal with this one myself but generally there's the same method to cleaning things.

Step 1: Aerate it.
It could just be that your chair (Be it car or office) hasn't had enough airflow. So, lets push some air past it. You could do so passively by just opening the windows/doors to get a good flow going past it or if you're more aggressive about getting that stank out you could point fans at it. Maybe even beat it with a stick a few times if it's one of those cloth seats to get the dust out. Be creative.

Step 2: Chemicals
Try spraying some Lysol or something similar on it. Could mask the scent/kill bacteria enough for it to be tolerable. If that's not enough and you don't think it'll damage the chair go ahead and hit that with some cleaner. Not sure about leather (You may have to go to step three for that) but for cloth I'd make some sort of wash using watered down cleaner, dump it on it/work it into the material with my hands and then dry it out somehow. If putting it out in the sun for a day or two works to dry it I'd do that, or maybe use a heater to do the job. (Far enough away to not make it melt/catch fire.

Step 3: Nuke that bitch
If you REALLY want that chair to stop stinking and none of the above steps worked it may be time to just scrap the material. Take a thread remover and take apart the seams holding the fabric together being careful to remember how it all fits together still. (You may want to make a drawing of the pieces fitting together before it's completely apart. Go to a craft store and get some foam or whatever that closely matches the material that's in it and carefully carve it to match the original. If the stink is in the fabric itself then get some new fabric and reupholster it at the same time. I don't think leather would hold enough of a stink to be a problem but this would be a good time to give it a good cleaning as well.

Then just sew it back together and whala, you've got yourself a non-stinky chair.