Remove a stain or clean a tricky surface safely

Help me clean this without damaging it. What needs cleaning: [e.g. "red wine on a wool rug", "hard-water marks on a glass shower door", "burnt pan", "grease on painted kitchen cabinets"] Material or fabric: [WHAT IT'S MADE OF - check the care label if there is one and paste it] How old the stain or buildup is: [FRESH / DAYS / MONTHS] What I've already tried: [PRODUCTS OR METHODS, so we don't repeat or react with them] Supplies I have: [e.g. "dish soap, baking soda, white vinegar, hydrogen peroxide"] Give me: 1. The gentlest method first, then stronger options in order, with clear steps (blot, don't rub, etc.). 2. Always: test on a hidden spot first, and what a bad reaction looks like. 3. What NOT to use on this material and why (e.g. vinegar on natural stone, heat setting a protein stain). 4. Chemical safety: never mix bleach with ammonia, vinegar, or other acids; don't combine products I've already applied without rinsing; ventilate and wear gloves for strong cleaners. 5. When to stop and call a professional (e.g. antique, dry-clean-only, large or set-in damage, suspected mold over a large area). Keep the instructions short enough to follow while standing at the mess.