6" scratch isn't that bad. There are DIY methods to fix this that i've used over the years. its not perfect but if someone doesnt know the scratch is there, they would not notice it.
a. touchup paint that is color matched to your car. Dealership is best, Duplicolor is OK.
b. 1500 grit wet-dry sandpaper.
c. 70-90% alcohol (good luck funding it today.
you are just using a little of this to clean the oil/wax from the scratch before painting. not critical
d. Meguiars ultimate compound
e. microfiber towels
f. polishing pad (foam) (if you have a DA polisher that works too. Orange pad form Harbor freight)
g. A flat sanding block to hold the 1500 grit sand paper)
2) fold the 1500 grit to a V and run it across the bottom of the scratch to remove any light rust. should see bare metal below.
3) Wipe with alcohol to remove any oil (fingerprints) or wax from the scratch and area
4) put masking tape on either side of the scratch as close as possible to the edges and fill paint.
5) allow to dry overnight
6) Paint will shrink back a little quite a bit.
7) fill again with more paint until it is slightly proud
8) allot to dry again.
9) remove the tape and sand with the 1500 grit sand paper on the flat block. you should only be sanding with +/- 1/2" r so of the scratch. Go across the scratch not with it. I also used circular motion when sanding. Rince often and continue until the paint is flush with the rest of the pain on the car. Be carefull to only sand the ridge and not through the clear coat on either side of the ridge.
10) when done will have a dull inch or so along where the scratch was.
11) then get the meguiars ultimate compound and go at it in a circular motion by hand with the foam pad. This will not cause scratched in the paint as it is pretty mild but can buff out the 1500 grit scratches with enough persistance.
12) once done use the alcohol to cleak the cutting oils off the paint, if you still see hazing, go at it again with the meguiars. It shoud get it all out.
13) once done apply a coat of wax.
Step back 10ft from the scratch then give it a look. If you still see it and are highly annoyed by it, you need a paint and body shop. I've done many of these and as long as the metal is not dented under the scratch, it works really well.
thanks but thats a whole lot more work then i want to do.
I may just clean it up good and cover it with black magic marker(its a black car).