I've actually found an amazing product. I've had terrible oxidation on my 66, it was waayyy foggy and have used product after product w/ barely any results. I even did the clay bay, which did nothing. I have also done a 3 part system that consisted of buffing, and it worked pretty good, but sadly the oxidation returned shortly after.
Anyway, the product I recently used and highly recommend is called Oxygone. I've only found it online and its from the same makers of Dri Wash 'n' Guard, which is a also a good product (it works like a wash, wax and sealant in one).
The cheapest I found the Oxygone for was about 10 bucks for 8 ounces. I've used about half the bottle to do the top, hood and trunk on my car (the sides were fine). I did apply the Dri Wash 'n' Guard right after, which I think helped me keep the results I achieved. That Dri Wash 'n' Guard is pricey though, like 40 bucks, but it lasts a while. If you don't wanna spend the money I'm sure a good (less priced) wax and/or sealant would be fine to apply after the Oxygone treatment.
Anyway, I applied the Oxygone treatment by hand and was amazed, you can probably get even better results with a buffer, at least thats what it says on the product. Although the oxidation is not 100% gone, the difference is like night and day, and I plan on using the other 1/2 of the bottle to see if I could get the rest of it off.
I honestly don't think theres a better product to get rid of oxidation and have recommended this product to my brother to use on his highly oxidized but otherwise nice RX-7.
Anyway, good luck, just do a search on google for waterless car washes, dri wash n guard, and oxygone to see what you come up with.