What this video covers
The clip covers wood, which behaves differently from tile or glass because it absorbs.
For light surface growth the approach is mechanical first: sand back with 100-grit to physically remove what has penetrated the top layer, then treat the cleaned surface. Cleaning alone leaves material in the grain.
The takeaway
Porous surfaces need material removed, not just wiped. If sanding reveals staining that goes deeper than the surface, the piece is beyond cleaning.
Read the full written guide: Mold on Wood.