[Eliot Ness]

As a reference I've saved FAQ's from the original Grillecloth.com site and will reprint them below:

"Optional Aging Tips (if needed or desired)

 
Here are two methods, in order of my preference, that may help you to alter the
look of the cloth beyond what spray starch will do and perhaps make it look more
weathered and worn. Obviously, if you want to do this you should do this prior to
installation.

Method #1: Use a strong solution of black coffee or tea or a mixture of both. It
may appear that you are going to ruin a good grille cloth, I assure you that will not
happen. The rayon/polyester will not take too readily to dyes and stains and once
your cloth has dried out it will look much improved over the original. The shine will
have been reduced and it will have a slight brown dullness to it. Whether you leave
it in for 20 minutes or 8 hours, the effect is more or less the same. Rinse in warm
water after removal to wash out the coffee smell.
 
Method #2: Use a very diluted solution of shoe dye. I use Fiebings because it is
soluble in alcohol. I start with a bottle of light brown, which costs around $3, and
dilute a small amount (somewhere between a thimble or a shot glass) in a ratio of
1 dye to 3 or more alcohol. You may want to start out very weak and work
backwards to be sure not to ruin your cloth. The shoe dye is very potent and will
permanently dye anything it touches including your hands, so be sure to use
gloves. At a ratio of about 1:6 it approaches the mildness of the coffee/tea
method.
 
Acknowledgements to all of the many collectors and restorers who helped make
these instructions possible."