Were you attempting to make 'go-faster' stripes?
Sorry - I'd say T-cut and then one of those 'colour magic' products would do the job. Check out Half-frauds - they do their only range of colour polish, slightly cheaper than named-brand. Or check out ebay.
What I wouldn't do, if scratches are superficial, is try and cover them with a coloured paint pen. Its dead hard to match the colour.
Thanks MissGuided for this helpful advice. I was going really slow and was shocked when I heard the noise. Very narrow gateway and I mis-judged it.