I made it at Techshop
This instructable was Runner Up in the Copy Cat Reverse Engineering Challenge.
Commercially available Grit Guards (http://www.gritguard.com) fit in the bottom of your car wash bucket and clean your wash mitt, brush, or towel, to save your paint from swirl marks and scratches. Once the grit is removed from your mitt, the guard acts as a settling filter, keeping the grit away from your mitt, so that you don't recontaminate it.
Grit Guards may be purchased for $9.99 + shipping and handling, and according to their website, is the "most cost effective method for protecting your precious painted surfaces from being scratched while washing your vehicle."
However, this instructable will show you how to make your own grit guard for FREE*, making THIS the most cost effective method to protect your vehicle!
If you must purchase one, Home Depot sells theirs for $2.60, which is still 1/4 of the price of a Grit Guard.
Tools (available at TechShop):
1" or 1-1/8" hole saw
Step 1: Mark the holes
(You may notice our bucket started out with a few saw cuts in it, after it was used as a makeshift sawhorse, making it the perfect donor bucket for this project!)
Step 2: Drill the holes
Then drill holes all the way around, near the center, then add a third set of holes in between the others.
You can go ahead and add another hole in the center if you wish, and you are done!
Step 3: Using your Grit Guard
Place your new grit guard in your 5 gallon wash bucket, and fill with water and your favorite car washing soap. Because of the way the buckets nest, the bottom of your grit guard will sit a few inches above the bottom of the wash bucket.
Start washing your vehicle, and each time you place the mitt back into the bucket, rub it on the bottom of the grit guard to release the dirt, grit, and grime. The soild particles will pass through the holes in your grit guard and sink to the bottom of the wash bucket, keeping your mitt clean and grit free.
There is certainly nothing wrong with the two-bucket method, and for the price (FREE), it is worth making a second grit guard if you choose.
Step 4: Storage
This lets you store all of your favorite soaps, cleaners, mitts, chamois, brushes, etc. inside the pail, and also provides a 'drip rack' for your wet stuff.
If you want, you may even add a lid, to keep all of your car washing supplies clean and organized.
By the way, that is my 1977 Chevrolet El Camino SS.
I have been designing products in the automotive, aerospace, medical, defense and consumer products industries for over 30 years. I am an "Inventor for Hire", so if there is something you need designed or built, just send me a message, or stop by http://www.lime3D.net, and maybe we can do business!