yes you can cut the bad leaves off. yes new ones will grow. my suggestion though would be to put more light on your plant so it won't stretch. just a suggestion though. (look at the front right girl of mine in the pic. you want yours to look like that. it took me two months to figure that out.) oh and topping is when you cut the main lead. when you cut the "bad leaves" off it is called pruning. you might also want to get a grow book to guide you through the process of growing. HAPPY GROWIN!!!!!!!!!!