To protect and enhance the design on your slate coasters after engraving, follow these steps:

1. Cleaning: Start by thoroughly cleaning the coasters to remove any dust or debris. Use a soft cloth and a mild detergent with water, then dry completely.

2. Sealing: Apply a stone sealer specifically designed for slate surfaces. This helps to protect against moisture, stains, and damage from heat. Choose a matte finish if you prefer to maintain the natural look of the slate.

3. Coating: Consider using a clear polyurethane spray or topcoat to provide an additional layer of protection. Ensure that it’s suitable for slate and safe for use on items that come into contact with beverages.

4. Storage: Store the coasters in a cool, dry place when not in use, away from direct sunlight to prevent fading or damage.

5. Regular Maintenance: Occasionally wipe the coasters with a damp cloth and avoid harsh chemicals. Reapply sealer every few years to maintain protection.

By following these steps, you can ensure that your engraved slate coasters remain beautiful and functional for years to come.