Okay so I'm doing a mk2 project and getting rid of the bumpers but they both a some small cracks nothing bad they are Ghia/xr2 bumpers This is my first project and trying to save a bit of cash is there any way of fixing the bumpers without damaging them as I wish to resell them? 

You could bind the cracks on the inside with fibreglass and resin, you can also do the same to the outside and sand back smooth and level, minor filler (if necessary) and paint. My little mk3 taught me all of this, it works and looks a treat 

If you're unsure of painting, either get back to me or leave it as repaired but solid parts for sale as chances are anyone purchasing will paint to match anyway