I am notorious for not labeling preserves. With almost 700 jars it’s generally not a problem. Generally. You see, there was that time that we went camping and I found out that raspberry jam and raspberry jalapeno jam look almost identical.
Dana found a simple solution:
Sharpie poster-paint water based markers. They work like a pen and was off with ease (slightly more work than washing a jar with no markings on it but less than one with a label that’s glued to it).