Scumming at Lead Edge Corners...

[spigot]

Have you tried water wetter. I think it was silvermaster water wetter or AB Dick. Sorry Can't remember. It can work on other plate types as well when experiencing gradual toning/buildup issues. I had an issue with a new CTP installation and made it manageable by testing out some old chemicals we had from poly plate days and the water wetter worked for that time. Although i havent seen the product for a while.