These are the Italian plurals, depending on the form of the singular
Since mezzaluna= half moon, the plural is mezzelune = half moons .

Passatutto doesn't change. Its literal meaning is Passa tutto = ( tool to) mill everything . Here passare is to mill, but the idea is that everything over the tool passes under the tool, grounded.

Anyway, to clean a passatutto is such an hard thing to do.. I hate it.