dégoudronner

A narrow, mostly technical verb: to strip tar or tarmac from a surface, most often a road (dégoudronner une route) during resurfacing work. Occasionally used informally and figuratively for clearing built-up tar from the lungs after quitting smoking (se dégoudronner les poumons).

• L'entreprise a dégoudronné la route avant de la refaire. — The company stripped the tarmac off the road before redoing it.
• Ses poumons se dégoudronnent petit à petit depuis qu'il a arrêté de fumer. — His lungs have been clearing out little by little since he quit smoking.
• Il faut dégoudronner cette allée rongée par les racines. — This path, damaged by roots, needs to have its tarmac stripped.

Almost always literal and tied to roadwork — the lungs usage is informal and metaphorical, not a recognized medical term, so it shouldn't be used in a clinical context.