You don’t need to remove the rockwool. The roots grow right out of it. If you plant clones in rockwool I advise to get a good root structure first. I cloned my plants, put them in rockwool, put them inside of a plastic zip lock bag with a bit of extra water visible at the bottom, and placed them inside the bottom of the light box I made that already had larger plants in it. I cloned twice the amount I wanted just to be sure I would have at least some success, and all of them did great. Now I have too many plants.
I did keep the zip lock bag sealed for the first few days (I puffed it up by breathing into it), then opened it for a day, and kept that process going for about a week before leaving it open for good. All of the roots were very strong and grew quickly. Hope this helps and good luck!
P.S. Don’t forget the root powder before you put the clones in the rockwool!