My uncle who did a career as a hand letterer (or sign painter) in San Diego California has a 29 Ford roadster that he takes to a lot of hotrod gatherings in Southern California and he taught me a trick that the "in the know" hotrodders use to keep their windscreens spotless. (It also works on chrome too!)

Bon Ami has has been making their original 1886 formula cleaner since, well, 1886 and it used to come in cake form and that is what you want to use if (and its a big if) you can find it. Bon Ami nows comes as a powder cleaner and don't confuse the red original 1886 formula with the gold label version. The gold labeled version has five added chemicals whereas the original 1886 formula is only soap tallow and a mineral called feldspar. Feldspar is super soft, yet slightly abrasive and like the package says, "It hasn't scratched yet". The gold label version is easier to find, most hardware stores cary the gold version but the red original 1886 formula is a more elusive cat. (Jaguar pun intended)

A soft cloth wrapped tightly around your index and middle fingers is dipped in water and then rubbed on the Bon Ami soap cake to make a slurry which is applied to your glass. You'll have to keep moistening the cloth and create your slurry a number of times to coat an entire glass windshield. (Well used Bon Ami cakes develop a scalloped depression in the bar from this action) It will look like swirls of hazy white when it dries and after it dries is when you come back with a clean cloth and polish the glass clean. Like removing wax, you'll need to keep using new clean sections of the cloth as you polish. You'll be amazed at how clean your glass becomes...cleaner than you've ever seen it as the difference is quite noticeable.

Sign painters when hand lettering a glass door will use Bon Ami to clean the glass as the soap tallow molecules literally attach themselves to the dirt that is in the pores of the glass. Yes, glass is porous when viewed under a microscope and that is why regular glass cleaners are not as effective as Bon Ami. The soap tallow molecules literally pluck the dirt out of the pores of the glass when during the polishing stage and this is why it is such a good cleaner of glass. The best actually. Photographers who used to make glass plate negatives first used Bon Ami to clean the glass before the light sensitive emulsion was applied to the glass.

The cakes are hard too find yet it is easy enough to make your own if you have some of the original 1886 formula Bon Ami. This hand lettering forum is where I learned how to do it and I have a different technique that I'll share next.

I dump two cans of Bon Ami in to a larger mixing bowl and slowly add distilled water (about four to eight ounces) until I develop a very thick pancake like battle with no lumps. You can always add more water so add it slowly as you don't want it too thin. I use a twelve muffin baking pan and I fill each muffin cavity to the top and I can pour maybe ten muffins using two cans of Bon Ami powder. Now you have to have patience as the Bon Ami cakes need to dry out. Its similar to how plaster of paris dries but it takes much longer and you need to "press" the cakes every so often starting in about five or seven days. By that time the skin of the cakes has hardened so it can handle being pressed. I use an empty small 4 ounce jar that Pesto comes in as the lid of the jar is just the right size to fit in the muffin pan. I firmly press down on the cake as hard as I can and sometimes I spin the jar as I press. You'll want to press it every couple of days for about three weeks or so and you'll know when the cakes are ready as they have lost about ¼ to ⅓ of their original height due to the pressing. Then its just a matter of turning the pan over and using a soft dead blow mallet to smack the bottom of the pan to dislodge the cakes.

So signpainting, 29 Fords and even photography all have something in common as do Jaguars!

 

Great feedback, just went to their website and took a look. They too endorse using it for glass, but only the Red box original formula. Mike, I don't think you stated this, maybe I read too fast, but would you mind confirming that the "New" formula is not to be used on glass and you were only referring to the old formula?
http://www.bonami.com/index.php/prod...wder_cleanser/
Thanks mate,

John

 

You are correct....... only the "Original 1886 formula" in the red labeled container can be safely used on glass as it only has two ingredients, soap tallow and feldspar. The gold labeled can has three extra ingredients that can scratch glass so avoid the gold labeled Bon Ami. Only the "Original 1886 formula" in the red container should be used.

Follow this link and at the top of the page it talks about the gold label...scroll down the page a bit and it talks about the original 1886 formula and it then talks about favorite uses for the 1886 formula such as cleaning glass.