Without going into the why and wherefore, the 914 has gotten itself covered in a fine (poor adjective, there) coating of concrete dust. After removing much of it with a v. powerful leaf blower, I am still left with this very thin layer of dust.

Being reluctant to "flood" the whole car with water and thereby possibly relocating this contamination into all the crevices of weatherstripping, body cavities and the (still clean) engine compartment, my best thinking is to utilize "Griot's Spray-On Car Wash". Having used this product a few times on both my motorcycle and the 914 to remove both light dust and minor road film with no adverse effects, I'm disposed to use this product very carefully, using clean micro-fibre rags and not allowing any foreign material absorbed by the rags to be re-introduced to the cleaning process.

Any suggestions or advice is welcome and very much appreciated.

And Pat, don't suggest dry paper towels to wipe the car off with........that's absurd, think of the environmental impact of those towels going into a landfill!

I can't fault the approach you outlined, however I have used KozaK dry wash cloth with much success. I see it is now handled by Lexol (http://www.kozak.com/Product_kozak.aspx#). Works great on the interior too. Removes the dust and leaves no residue.

I originally feared the possiblility of grinding the dirt into the paint. Used it on my daily beater, with pressure, and had no adverse results. Love the smell.

You used a floor cander to clean the garage floor, didn't you?!

Do what you wish, but I would do differently. Then again I have a monstrous collection of terrycloth towels, blood rags, etc.

What you need are two 2-5 gallon buckets and a bunch of old (clean) terrycloth towels. One bucket should have 2 gallons of water and about a quarter ounce of Ivory Liquid (others brand are more harsh). The other bucket should have nothing but clear water in it. Use the largest tc towels you have (old is best, and you ARE old & should have plenty). Dip a towel into the first bucket, with the detergent in it, wring it only to the point of not dripping, drape it on one side of the 914, reach over & grab it & pull it softly accross the car. Turn it over & do the same on the same spot.

Put the towel aside & reach for bucket #2, which should have another tc towel resting in clear water. Wring the towel out slightly (dripping is OK) & swipe it across the same surface, turn it over & do it again. Now's the time to use the microfiber to dry the surface you just cleaned. Be sure to set aside all towels from this procedure - do not use them again, until they've been washed.

Do the same procedure for the next strip of cleaning - DO NOT use the same towels! Concrete is terribly abrasive - wash them before ever using them again.

Repeat with fresh towels (never dip them back into the buckets!) until you've cleaned all painted surfaces.

Once the upper surfaces have been cleared of concrete dust you can use any goo of your choice to remove the dust from the ancillary crevices, like door jambs, f&r trunk seal tracks, etc, but use clean cloths for each area.

I've used this method for over 20 years (though I've never had to deal with concrete dust) and my finish is nearly perfect.

I would follow the whole ordeal with a fresh pasting of carnuba, or your wax of choice.

Yes, I'm anal about my paint!

Hope this helps.
Pat

First of all, we're talking about portland cement dust - not concrete, which is a mixture of sand, gravel & portland cement.

Paul -

So if it is "cement" - then first carefully pick off the gravel one by one, as the VP blower probably didn't budge them!

Seriously - second - you want to try to remove 99.99% of that dust DRY because water starts the process of setting the cement, and if you thought hard water spots are tough to remove - try portland cement! A auto detailing type of vacuum at a tight distance to the paint surface without touching should suck most of it up, then single use microfiber with some static attraction should work to get as much off dry as possible - from the fine film of dust.

Also of concern, portland cement is a very strong lye type base, so it will eat into your paint once wet. I know, as I had the misfortune of having my 85 BMW 325e parked at LAX for a week while I was at a conference up in Portland, and it was the week of the big fires a few years back (04 or 05 I think), when the ash plume went over LAX & closed the airport at times - it was on the news. Well wood ash also makes lye when wet, and the sea mist/dew at nights turned that crap into a cement like base mixture which "ate" the clearcoat on my bimmer!

Your best bet is to FIRST carefully get off everything you can DRY, using a vacuum, single use soft terry or microfiber, etc.

Then once you get 99.99% off dry, go to Pat's method or similar in damp - not wet mode. It would also help to add something to the water to neutralize the base of the cement dust.

So Paul - who dropped the bag of Portland Cement or Concrete in vicinity of the 914!!??

I only say that cuz I did that DA move myself a few weeks ago on a run from Home Depot in our 88 Westy!

PS _ "base" being the opposite of "acidic" but just as caustic to paint, etc. Hopefully I'm using the right term "base," but Pat the chemist can correct me if not.

I would start by using an air compressor set on its highest pressure and blow everything possible off first at close range, then go for the washing methods. A leaf blower will not impart enough focused pressure to remove all the dust. Another possiblility might be to use an adhesive lint remover type tape and just lift it off by hand, carefully not rubbing it in, but thats a lot of work. Even blue masking tape would work.

Dragging anything across the dusty surface will scratch it. Powdered cement is a fine abrasive so the dust should be lifted or floated off, not rubbed/wiped off.

Or you could just drive it real fast... Nah, that wouldn't work.

Update on car cleaning.

This "fallout" IS concrete dust, the result of a contractor literally sawing out a cracked section of concrete right in front of the garage doors. They came and cut, removed the old cracked slab, and poured the replacement, 1)earlier than scheduled, and 2)when I wasn't home. Their work was fine, as was the concrete dust. There was not Portland cement dust, thankfully, to deal with.

The 914 clean-up is 98% complete. I used a combination of additional high pressure (compressor assisted) blow-off, multiple water buckets, and Griots Spray On Car Wash to clean the car. The Griots product seems to have very slippery properties and combined with multiple clean micro-fiber towels, the resultant finish appears, at least under my garage lighting, to have escaped any damage. Bright, sunny days seem to be in short supply here in the River City, so I'll have to wait for full-on sunshine to determine the success of this procedure.

Thanks to all for your suggestions, help and guidance.