Since we have been a user with Cal Cover Duster for 20 years and have the following comments....
1, For maintenance, here is direct lift from Cal Cover staff...
"You really do not want to try and clean or rinse the California Car Duster until it is a last resort.
For daily maintenance, simply shake out the car duster or clean it thoroughly with an air gun. The mop will discolor with continued use, but keep using the car duster as long as it is picking up the dust..."
2. Regarding availability
They have (2) versions (1) with a wooden handle $24.95, and (1) with a plastic handle $19.95. They also have a couple of smaller versions available as well..
Just my $0.02... 
The following is from California car cover whom I believe was the originator of the product. Bought my first one at a Pleasanton NSRA or Good guys event about 1985 or 6 ?
LINKY The link is dated 2005.
The California Car Duster can go years without washing and in most cases works just as well as the first day. It is best to simply shake the duster out after use and on occasion blow the mop out with air. From most customer experience their dusters have lasted in the range of 15 years.
If you do feel the need to wash your California Car Duster, here are the steps:
1. Wash the duster by hand, leaving the mop on the handle.
2. Clean the duster in cool water mixed with a small amount of a mild detergent (i.e. Woolite)
3. Rinse clean with fresh, cool water.
4. Let the duster air dry (this may take a couple of days.There are others making the product and that is likely where the conflicting information is coming from. I did try the Woolite treatment on one 30 or so years ago. It helped but never cleaned the same. Just wanted to clarify what I posted
