(I think you can also find variants where it's "caked on to"..I've only used it verbally, so I'm not sure which version is preferred) Let's imagine you use a knife to spread jelly on your bread. If you clean the knife right away, the jelly is easy to wipe off. If you wait a few hours, the jelly solidifies and is harder to clean off. In this case, we'd say the jelly is caked on..or caked onto the knife. When it's caked on, you really have to scrub to remove the substance. So, in German I'm not sure how to express this situation. I'd try: Die Marmolade klebt fest am Messer. Or Die Marmolade ist schon an dem Messer festgeklebt. But to me festkleben is just sticky and difficult to remove, not necessarily hard and difficult to remove. I've seen angebacken as a translation, but that can't be right in the absence of heat. Would a variation of abgehärtet be preferred, such as "Die Marmolade ist schon an dem Messer abgehärtet"? Thanks for any suggestions!