A better system to remove that crud would be CO2....dry-ice.
They make different sizes of dry-ice beads that work the same, but they just evaporate after blowing the crud off leaving no glass residue behind.
The glass beads are considered both an environmental and a health hazard these days.
There are some people I know in the oil patch who used to do a lot of sand-blasting, but they told me that there are all these new environmental
regulations which make it expensive and time consuming so they bought dry ice blasting equipment.[video=youtube;l_9nITRz--0]http://www.youtube.com/watch?v=l_9nITRz--0&feature=fvw[/video]
[video=metacafe;1458498/dry_ice_blast_cleaning_cryogenic_institute_of_new_]http://www.metacafe.com/watch/1458498/dry_ice_blast_cleaning_cryogenic_institute_of_new_ england_inc/[/video]