I have tried toning cyanotypes with tea with varying degrees of success (or failure). Often, but not always, stains spoil a print that might otherwise been successful. I have tried hot tea, warm and cold, I have tried "stand" toning and have also done it moving the tray without interruption while the print is being toned. I have tried different teas and different papers, but there seems to be no predictability at all as to when a print will be spoilt by a stain or not. Any tips, please?