complex surface shelling

 From:  malvin
Hi Michael hi Danny

I attach the file where I tried to shell the surface of my design for a pendant
I could not shell the whole thing so I blew up the surface and shelled it in parts but could not join them together and remove extras (I tried Boolean union, merge)
I did not shell two small top corners so this has to be fixed also

Please take a look – you might have an idea how to merge them together and remove extras

Here the thickness is 1 mm.