You are here:

Construction & Contractors/black slate stone - watermarks



One of our flower pots was leaky and left a circular white watermark on the black slate fireplace surround. Unfortunately, the black slate has not been sealed by the owner of the apartment. I am looking for some expert advice on how to remove the mark without causing further damage to the surface of the slate. Also, I wonder if you could recommend any useful products, e.g. HMK stonecare. In which US stores could I buy these products?

Thank you very much in advance for your help.


Sorry for the delay in responding.
I may have spoken to you on the phone, but try using White Vinegar (mild acid) straight out of the bottle.
It is already diluted to about 8% so no worries of harming slate.

Allow to dwell on surface for 15 minutes, then scrub with a scrubbing pad.
Rinse well with water.

If this is not strong enough, you may need to use a stronger acid.
Also, I would suggest using HMK R55 Intensive Cleaner.
These products are only available online or through select stone care professionals.

Let me know if you need further assistance.


Construction & Contractors

All Answers

Answers by Expert:

Ask Experts


Torin Dixon


Questions concerning Natural Stone Fabrication and Installation including: Marble, Granite, Limestone, Slate, Soapstone, Bluestone, and Travertine in Slabs and Tiles. Expert in natural stone cleaning, sealing, protection and restoration. Distributor of HMK Stone Care Products; Sealers, Cleaning Products, Stone Maintenance. Expert in stone and tile flooring, sealing and maintenance issues. Stain removal from stone. Importer and Distributor of slab stone for residential and commercial applications. Stone carving Stone restoration


I have worked in the Dimensional Stone Industry since 1977.
California Contractors License 1989
Former owner of Prestige Marble & Tile (So. Calif.)
Current owner of Elegance in Stone (Missoula, MT)
Current Owner of Montana Stone Gallery,LLC Missoula, MT
Owner of Distributor of natural stone maintenance products

Missoula Building Industry Association
Montana Building Industry Association
Flathead Building Association
National Association of Home Builders
Member of the Marble Institute of America
Former member of the National Tile Contractors Association

Slippery Rock Gazette-Stone Industry Publication

Journeyman Marble Mason, Bricklayers and Allied Craftsman Union #2
California Contractors License 1989-1997
Montana Contractors Registration #70932IC
Importer of natural stone slabs. Owner-Director of Montana Stone Gallery a regional Importing and Distribution company located in Missoula, MT

Past/Present Clients
Thousands of commercial and residential installations of stone slabs and tile in bathrooms, kitchens, showers, flooring, fireplaces over a 34 year professional career.

©2017 All rights reserved.