This is an actual contribution of useful info by HK.

I like the Weather Tech type floormats with the cross grids.  They don't
slip, as they hold the water and cr*p that gets on your dirty soles.
But they look awful fairly quickly.
What to do?  Hosing off doesn't produce good results.  Brushing with soap
is a necessary.
When they dry, they often spot up badly.  Again, poor visual aesthetics.
What to do, you say?  They need to be shined up.  Answer:  Get some of your
favorite Armor All type stuff and spray on.
The problem is all the ridges and valley's won't accept the cleaner, and
you can't rub it uniformly.
Whaaaaat happen?  What You say?
Get a handy stiff bristle brush and a shop rag or fairly thin towel.  Spray
it with Armor All stuff too.  In my case, I use ultra high tech high perf
Formula 2000 from Tortoise Whacks.  Great stuff, bright green bottle.
Then brush the cloth in all directions of the ridges, from the sides at a
angle, and straight.  Takes a few minutes to be sure.  But like any job,
the extra is worth the excellent results.
Now gentlemen, and ladies, go and clean!!

your humble servant
HK