So my car mats look really bad. Are they machine washable?

 

No!, get one of those rental carpet cleaners from your box store with the cleaning wand and some carpet cleaner and elbow grease.

 

I had the same problem. My wife went to work on them. Her steps were;
1). spray the Matt with greased lightning and scrub with a stiff nylon brush.
2). spray with water to remove most of the greased lightning,
3) we put them in the washer and run through a couple of times to remove the rest of the G.L.
4).allow to air dry.

they actually look good.

this worked for us. the matts are tan colored.

good luck!