If you have an alloy boom I wouldn't bother re gripping it, the time it takes, you would be better off just buying a new boom. It takes hours to get the old grip off you could just go to work instead and then nuy a new one!
I just re gripped my boom but did it because it is a full carbon so kinda expensive to buy a new one. I used engine degreaser to get the grip off, I think it worked well but was still a pain