Huh, I’d never heard of this before: CRV Black Death, an affliction that affects Honda CR-V’s of our vintage. From the article:

All too often, it will self-destruct, shattering its internals and forcing the bits and pieces through the rest of your AC system. The microscopic metal shavings mix with the lubricating oil and create a tough “black” sludge that clogs the narrow passages in the system and is impossible to clean out completely.

I wonder if this is why our A/C system has never really felt like it was up to snuff? We had to replace ours last year right before we went on vacation; perhaps this was the problem.