bbqsoup

I have the black ones and yeah those tiny pores just suck any dirt in and keep them there. The foam window cleaner may work as it lifts the dirt. Tires cleaner may also work too. Pressure spray could also do the trick.
I couldn't get the dirt out with my garden hose spray so I'll try the foam cleaner or the black tires cleaner.

Acrad

Sorry.. I don't have any tips. I have black ones in most of my cars. I have some OEM all weather in another car and even those are a bear to keep clean. I have used Simple Green on those latter mentioned mats and no ill effects but not Weathertech as well.

Jacket

I use a scrub brush and a cleaning solution I bought some years ago. I find that hoses and pressure washing alone isn't nearly good enough and that you have to get down on your hands and knees and scrub the mats. I would think that Dawn dish soap and warm water would be a good alternative that most folks have under their sink.

MX5NES350

I use Simple Green (Purple) which is a bit more aggressive than the regular stuff. I used it on my vinyl fence at my old house and it worked well in full strength (non-diluted). Going to a car wash and hanging them on the mat holder for a good pressure washing will help as well.

IanB2

We live in Canada, and winter is long. We always buy bigger, aftermarket floor mats for this reason. I've got Weathertech Digital Liners in my '04 GX470, and we had Husky liners in our 5th gen 4Runner. Both were good, the WT's after many years are starting to curl, mostly on the cargo liner. The Husky's came in the 4Runner when we bought it, they are thicker than the WT and good quality, but only come in black.

For our new-to-us GX460 we wanted something that would match the sepia/brown interior, so the Husky was out. It had the flat/honeycomb pattern Lexus all weather mats already, but the carpet condition confirmed they weren't enough protection. Weathertech has launched a new HP line of floor liners, and they come in espresso/dark brown, so I decided to give them a try, ordered for the 1st and 2nd rows. They had to be manufactured before they shipped, we were waiting about 6 weeks for them, which might not be out of the ordinary these days, but it was a lot longer than I wanted to wait.

When the finally arrived, initial impressions were good! The material is much thicker than my old WT's, and there is a lot of additional structural elements to stiffen (specifically the front row ones), they are very beefy mats! Due to the additional stiffness, they need to almost be wrestled into place, the nubs grab the carpet and the shape doesn't distort easily, but once in place they fit perfectly. The holes for the locking tabs are robust, these don't shift around at all. We've had them for a week or so now, and I have no complaints.

IanB2

And some installed pics:

bbqsoup

They do look thicker than the old/regular one. Do you have the cargo area too? One thing I don’t like WT for the back is it slides very easy and I don’t want to cut a slot to tie it down.

ASE

Agree ... I use WeatherTech's in the front, rear ... but use the rubberized OEM pad for the cargo area for the reason you stated. The heavier OEM cargo pad stays put, and items are less likely to slide around on the pad during spirited driving.

IanB2

Due to the 3rd row seats, I will not be going Weathertech for the cargo area protection.

I have ordered a Canvasback system for there, which I can detail when it arrives. They JUST came out with a dark brown color, and I'm having them stitch some velcro hook strips on the one side so my dog's bed has something to grip onto. I have Canvasback in our 5th gen, and the only complaint was the material was too slippery, and the dog's bed ends up shifting and sliding around, so I came up with this idea and they're great to work with on custom details.