Removing polyurethane from a slate outdoor table can be tricky, but with the right approach, you can restore its natural look without damaging the stone. Here’s a step-by-step guide to help you:

1. Assess the Surface: Check if the polyurethane is water-based or oil-based. Water-based coatings are easier to remove.

2. Gather Supplies: You’ll need a paint stripper (citrus-based for eco-friendliness), a plastic scraper, steel wool (fine grade), mineral spirits, and protective gloves.

3. Apply Paint Stripper: Spread a thick layer of stripper over the polyurethane. Let it sit for 15–30 minutes until the coating bubbles.

4. Scrape Gently: Use a plastic scraper to lift the softened polyurethane. Avoid metal tools to prevent scratching the slate.

5. Clean Residue: Wipe the slate with mineral spirits to remove leftover residue. For stubborn spots, lightly scrub with fine steel wool.

6. Rinse and Dry: Wash the table with mild soap and water, then dry thoroughly.

7. Optional Sealant: If desired, apply a slate-friendly sealant for protection.

Always test methods in a small area first. With patience, your slate table will look as good as new!