Ospho is phosphoric acid, a rust treatment, I'd say the problem is using it over paint [of an unknown type/composition], when it's intended to be used on bare [rusty] metal I'd suggest stripping the gooey areas back to bare metal
"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir "When we tug a single thing on an old truck, we find it falls off" ~ me Some TF series details & TF heater pics
