I had looked into this several years ago. The Swiffer dust mops use static to capture and contain dust particles. That would make this a huge ESD concern. Electrical SMT equipment is grounded so any charge potential generated would be dissapated. I had determined that the use of the swiffer was acceptable for machine cleaning/maintenance as long as there was no chance of contact with a PCB assembly. This maintenance was performed on a daily frequency (AOI equipment) in the AM before any product was staged at the equipment. I beleive that use on the equipment only is safe but I welcome any comment on the subject.