Some time ago I read that you can extinguish bad smells from old objects by putting them into cat litter for some while.
When we got the bus, I thought about that trick as a good thing against its smell. Actually it wasn't. Instead today I had to realize what a mess I made. I found myself for three hours trying to get the small little clay pieces out of the carpet. Like Sisyphus. I had to vacuum over and over again. And still you can see little white pieces skipping when you brush it firmly.
Lets face the positive: the smell is gone!