Many, many years ago, we used to clean engines with Bon Ami. We had several "skeeter beaters" at the salvage yard and would take them out on a deserted road. These were all pre-catalyst cars and trucks. Take the air cleaner off, run the engine at about 3/4 throttle and shake Bon Ami into the carburetor. It would blow huge clouds of white powder out the tail pipe. Several cleared right up and all of them reduced oil consumption. We also used to use Bon Ami to clean windshields but now the cans say NOT to use on glass. In the 60's and earlier, glass was glass. Now windshields have coatings that will mar.