How to remove bird dropping residue

[zmyride]

I sprayed Meguire's Detailer to remove a couple spots of bird droppings and add a couple layer of wax soon after, but i still see some etching which i couldn't remove.

I think the droppings must have been on my car for two hours max. as soon as i got home, i removed it immediately.

it's hard to see but if i shine a flashlight at a certain angle, i could see the etching.

BTW, I talked to one of nissan engineers before and he told me since the Z use aluminum doors and hood, the paint doesn't hold very well. that's why paint on the Z is so sucky.

anyway is there anyway i can remove the residue/etching? would a clay bar work?