Why need clean wave solder pallets/fixtures

Why need clean wave solder pallets/fixtures

Why need clean wave solder pallets and fixtures/jig ?
Solder pallets /fixture after repeated use, surface will residue fluxing etc. these impurities will affect the soldering quality, lead to adverse phenomenon such as virtual welding, black spots.In order to ensure the soldering quality,the fixture /jig need cleaning remove surface flux residues.SAM Patent design SM-8400N wave solder pallets clean machine with Washing-Rinsing-Drying clean process , Fully automatic ,could thoroughly remove solder pallets/Jig surface flux residues .