Home Depo has stuff called Bix, that I hear is very good?
I have also hear (all bad) about a tape you put on and peel off later.
Then there are those that just us a sharp scraper and scrape it off, being careful not to cut into the gelcoat.
There is no real easy way to do it!! Its eaither goining to be a time consuming job for you, or you are going to pay someone to do it.
If you don't count your time for much then its cheaper to do yourself.
I sold my boat so I would not have to do it
The new boat I bought was alreay done for me.
Eaither way get her done!!