Are all clay bar kits created equal.

I have original paint on my 1970 Camaro, so it has some really fine cracks in the paint.
I used the Mother's clay bar & spray on it and it was a WORLD of difference. Cleaned out all the surface of the paint. (Then I used Liquid Glass to seal it up)
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Tried it out on my 2005 Jeep, but with the paint a lot newer, I didn't see much difference.
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So that's my experience with clay...works great on older paint, not really noticeable on new paint...