It is vulcanised rubber. Best way to treat it if the smell is too much is to wash in boiling water for a few hours, in a drum over a fire would probably be best. Add a half kilo of sulphur into the water as well. That way you vulcanise it fully, and then it should smell less like new car tyre. Otherwise you just leave it out in the sun on a roof for summer, which should bake it nicely. Leaving in the cold dark worsens it, you need to get it nice and hot.
Hmmm ... that sounds interesting, gonna try that on the weekend. Thanks SeanB!
Nope, did not work at all. Smells at least as bad as before.
And just to be clear, it is a new car tyre, rubbery smell.
I also question whether the sulphur in boiling water is doing anything, the sulphur powder came out of the water the same condition as I poured it in. Obviously sulphur is insoluble in water and I think 100°C is too low for any expected chemical reaction with the sulphur.
I boiled it for 6 hours, during which loads of the lovely rubber and a little bit of sulphur smell pervaded the vicinity of my cauldron. That didn't make me very popular with everyone around me
At first the fact that the boiling forced out the rubber smell in high concentration made me hopeful, but hanging the mat outside for a day now, the smell is just as bad.