boilerplate contamination

Why raw web data broke your fine-tuning and how DOM targeting fixed it

Boilerplate contamination is the silent killer of fine-tuning, and this post names it clearly. Navigation menus and cookie banners leak into training data, and the model starts hallucinating half-rendered HTML. The fix is aggressive DOM-targeting combined with rotating residential proxies that deliver the same DOM a real browser sees. Deduplication order also matters more than expected. For a deeper look at data flaws that slip past standard checks, see "The Four Data Flaws That Slip Past Every Validation Check."