Room temperature, heat speeds it up, plastic soak tank preferred, pre-clean item, do not use any other chemicals or solvents to pre-clean, rinse item and immerse, length of time varies depending on severity of rust, light surface rust requires 5-30 minutes, moderate rust up to 4 hrs, deeply rusted parts overnight, check progress periodically, some items not fully immersed may experience carbon etching at the water line, rinse with water, for short term rust inhibition, dip in rust dissolver and allow to dry. I don't recommend to do that...it's better to spray a light coat of MP-50 or equal for temporary rust inhibition for the natural look or you can clean and paint or coat the part later. It also loses it's oomph after a few uses.