[DuckNut]

They yellowing is oxidation. It can be clean to some degree but it will not be as white as the new lid.

There is a post on here not too long ago of someone who did their entire hull and it came out fantastic.

 

[cvilt]

I used Buff magic followed by Pro Polish and it was pretty easy. Ducknut is right it will be better and very shiny but I think the yellowing gets deep.

 

[ASB73]

Wets sand with 400, 800 then 1000 and wax it up

 

[cvilt]

Buff Magic starts at 400 grit and as you work it turns to 2000. Much easier than sanding if you have a buffer. But sanding sure works nice

 

[jms]

Wets sand with 400, 800 then 1000 and wax it up

starting out @ 400g is asking for trouble,you're gonna sand right through the gel...

then wax ? you forgot something,compound...

if you're smart,you're gonna forget all these "miracle" products - stick with what works...

3m heavy cut compound,followed by waxing with colonite fleet wax - you're gonna need a real variable speed buffer - not a toy orbital waxing product,use the compound with the buffer,followed by waxing...

as far as getting the color to match - it's gonna come close,but,it will never be a 100% match,the gel coat,it ages,shrinks and color fades...

 

[ASB73]

Wets sand with 400, 800 then 1000 and wax it up

starting out @ 400g is asking for trouble,you're gonna sand right through the gel...

then wax ? you forgot something,compound...

if you're smart,you're gonna forget all these "miracle" products - stick with what works...

3m heavy cut compound,followed by waxing with colonite fleet wax - you're gonna need a real variable speed buffer - not a toy orbital waxing product,use the compound with the buffer,followed by waxing...

as far as getting the color to match - it's gonna come close,but,it will never be a 100% match,the gel coat,it ages,shrinks and color fades...

I have never had a problem starting with 400 and in fact I just did my dolphin console with this method.
I used the all in 1 3m cleaner and wax and not a separate compound and wax. It looks killer