ok, clay is fine IN THE RIGHT CONTEXT. You should use it as a last resort... first use the reg. wash, maybe polish if you need to then move up to glaze, then as a last resort use claybar... but you must use that stuff really carefully!

If you are trying to get some enviornment "gunk" sap, bugs etc etc, i would reccomend instead of first using the clay bar try using during the wash period a degreaser... I have heard the ONE GRAND degreaser is good, and i have used and use the P21S Citrus Degreasr, that stuff is great for taking out that "gunk"

anyway, you gotta recognize that a clay bar should really be used sparingly and only if your paint really needs it, but first exhaust the more mild routes ahead of a claybar, or you are un-necessarily wasting time/money on a claybar!