Halamid is able to disinfect any surface and hence also these cooling pads. With the fans on hold, these pads can be sprayed with a 1% Halamid solution. Let it dry to the air and restart the fans. If visually dirty, then spray with a detergent beforehand. If dirt still comes off after spraying the Halamid solution (e.g. dead algae) then spray with water afterwards. The pads should be perfectly clean after this treatment.