I tried some PO85RD, but it didn't really do anything. Granted I didn't rub too hard because I didn't want to cause additional damage. Is this the right type of polish and should I try rubbing a little harder or do I need a more aggressive product?
Working on clear coats in the context of removing defects without instilling defects at the same time is actually pretty hard to do. Most, (not all but most), products that work by machine don't also work by hand with the same results.
As pointed out by Ron, PO85RD is a finishing polish and a DAT product, chance are good it will have no effect at all except if you get frustrated and start pushing real hard you'll put toweling marks into the paint.
The product that I've used to date that works the best by hand to actually remove "Below Surface Defects", that is things like scratches, swirls and etching that are "in" the paint is the SMAT product by Meguiar's. Whatever this abrasive technology is that they've created it really works well by hand. Removing an etching means removing a little paint and that's the tricky part, how do you remove a little paint and level the surface without instilling scratches at the same time...
Like I said, working on clear coats in the context of removing defects without instilling defects at the same time is actually pretty hard to do.... so you want to use the right product, good technique and the best application materials and removal cloths you can obtain. Everything is a factor when working by hand.
It's actually real easy to get good results by machine, it takes more skill and experience to rub a clear coat out by hand than machine.
Do like Mike P suggested and get some ScratchX. I would get Ultimate Compound as it will take care of most scratches and will finish down with no marring.
I recommended ScratchX mostly because I don't know the skill level of the OP but my guess is the opposite of years and years of experience plus they're working on a black car.
Here's the real way to approach this problem, if you're going to take ownership of your car's appearance, as in washing and waxing the car, then you need some "Tools" in your Tool box and if you're working by hand then having a few products in your tool box would be a good idea, bet the ScratchX and the Ultimate Compound, then when you start, start with the least aggressive product to get the job done, if the first product you don't try doesn't get the job done then you can alway substitute a more aggressive product.
The Aggressiveness Order of SMAT Products - This might surprise you!
Super Micro Abrasive Technology = SMAT
From left to right, the most aggressive to the least aggressive SMAT products
From the most to the least aggressive...
M105 Ultra-Cut Compound/M95 Speed Cut Compound = The same in abrading power
Ultimate Compound
ScratchX 2.0
M86 Solo Cut & Polish Cream
D151 Paint Reconditioning Cream
SwirlX
M205 Ultra Finishing Polish
