1. Acidic Foods (Like Tomatoes or Vinegar-Based Sauces)
Tomatoes, citrus, and vinegar can strip the seasoning off your cast iron. That black, nonstick coating you worked so hard to build? Acid eats it away. It can also leave your food tasting metallic—definitely not the flavor you’re going for.

2. Delicate Fish
Cast iron is all about high heat and heavy-duty cooking—but delicate fish like tilapia or flounder? Not a great match. These flaky fish tend to stick to the pan and fall apart, turning your dinner into a frustrating mess. Stick with stainless steel or nonstick for fish.

3. Sticky Desserts (Like Caramel or Fudgy Brownies)
Unless your pan is very well-seasoned, baking sticky or sugary desserts in cast iron can result in a burned-on mess that’s nearly impossible to clean. Plus, any lingering savory flavors can sneak into your sweets—nobody wants garlic-scented brownies.

Bonus Tip from Grandma:
Never soak your cast iron in water, and always dry it thoroughly after washing. A little oil and love goes a long way in keeping it happy for generations.