How to Clean Timberland Boots (with Pictures) - wikiHow
Update to my last post: the Timberland Boot Kit helped a bit, with a few cycles of brushing and cleaner and then conditioner. But what ultimately helped most was dried bread. :
Amazon.com: Timberland Boot Kit Shoe Care Product Set, No No Color, One Size Regular US : Clothing, Shoes & Jewelry
5 Tips on How to Clean Timberland Boots | Boot World
How To: Clean Your Suede, Nubuck and Canvas Gear | Timberland - YouTube
How To Clean Timberland Nubuck and Leather Boots at Home