[ardoski14]

I'm assuming you are referring to the U-coolers on the front of each engine.  I would try to use a pick & remove any remains of the old zinc, but, as the coolers are pretty much closed vessels, I'd probably leave them behind to eventually be eroded away by the raw water flow.  To some degree, whatever is left in there may hinder the insertion of the new zinc & have some effect on future flow until it breaks down further.
The zincs in your pics show them largely intact, but the extensive erosion at the base will only cause you to have the same problem again.  That being said, I change mine every season.  Very inexpensive & easy to replace.  As you may already know, the zinc can be unscrewed from the brass cap & a new one installed, lowering the cost even more.
Hope this helps

That was my concern of just leaving it in there. So I think I'm going to remove the cooler and remove the old zinc. If there was room I think I could pull it out, but location doesn't allow that. The picture attached is the starboard cooler which removed with no problems.  Thanks