Sounds like your ink is too loose vs. tacky. You might want to add mag to it especially if it is breaking up on you and making little floaties that close your plate. We used to add gum to the water – quite a bit so that the non-image area resists the ink as it absorbs the water during the sponging process. We also used to add toothpaste to the water to act as a scrubbing element to keep the plate clean – no lie. It is akin to some lithographers dumping mag and gum arabic in their sponge water to make a very basic fountain solution. Yes, the plates smelled nice and minty. The toothpaste has to be paste and not gel – the little grits acts as an abrasive. You can clean your plate while you are inking it up. Sounds squirrelly but it works. I learned this method at Tamarind. Somewhere between playing with the gum water mixture and adding toothpaste and having a dedicated cleaning sponge you may find some success. We made color separation editions with punch hole registration – the images were color separated and the toner was fused onto each plate that had a primary color. I have no idea of who came up with this approach but like in printmaking – you will get another answer from somebody else. I taught pronto plate printmaking as a graduate assistant. The kids got a kick out of putting toothpaste in the sponge water.