How to clean flint

Having our old cottage re-tendered, hacked it off already and there is a 18”- 2’ bit at the bottom which are flint stones. Love the look and would like to try to keep them exposed to show the character. however obviously a lot of cement on many of them and just wondered if there was something we could use to dissolve the residue or in some place, remove chunks of cement to clean them up ? Any suggestions please?!!!

Asked by Jill on 4th Jun 2024
Expert Trade Answers
"Brick acid is what all biulders merchant sell for just that purpose."
Answered on 4th Jul 2024 - Member since Jun 2024 - report
"Try Brick Cleaner (Acid) works well on bricks when removing cement residue, Most builders merchants sell them."
Answered on 4th Jun 2024 - Member since Mar 2024 - report
"To clean flint with remnants of old cement mortar, you can use hydrochloric acid cautiously. Prepare a 10-15% acid solution by pouring the acid into water. Work in a well-ventilated area with protective gloves and goggles. Apply the solution to the cement using a brush or by submerging the flint, and let it sit for a few minutes until the cement starts to dissolve.

Use a synthetic bristle brush or wire brush to remove the softened cement. If necessary, reapply the acid solution and repeat. After cleaning, thoroughly rinse the flint with plenty of water to remove any acid residue.

Alternatively, you can use vinegar, a milder acid. Soak the flint in vinegar or apply it to the cement and leave it for several hours or overnight. Brush off the softened cement and rinse the stone thoroughly with water.

Always test on a small area first to ensure the flint won't be damaged, and handle with care throughout the process."
Answered on 4th Jun 2024 - Member since May 2024 - report
"use brick ascid and wire brush .make you use gloves and eye protection"
Answered on 4th Jun 2024 - Member since Apr 2020 - report
"Brick acid, but be very careful make sure your eyes are covered and all your Skin and use a wire brush"
Answered on 5th Sep 2024 - Member since Aug 2024 - report
"Exposing and cleaning flint stones can add a wonderful character to your cottage. Here are some methods you can use to clean the cement residue from the stones:

1. Manual Removal
- **Chisel and Hammer:** For larger chunks of cement, you can use a chisel and hammer to carefully chip away at the excess mortar. Be cautious to avoid damaging the flint stones themselves. Work slowly and carefully.

2. Chemical Methods
- **Muriatic Acid (Hydrochloric Acid):** This can be effective for dissolving cement. Dilute the muriatic acid with water. Apply it to the cement residue using a sponge or brush. Let it sit for a few minutes, then scrub the area with a stiff brush.

3. Commercial Products
- Consider using commercial concrete or masonry removers designed to dissolve cement. Products like **"Dissolve"** or **"Concrete Cleaner"** can be effective. Always read the manufacturer's instructions and ensure compatibility with your flint stones.

Good luck with your project, and enjoy the beautiful character of your cottage!"
Answered on 24th Sep 2024 - Member since Jun 2016 - report
"get some brick acid should clean them up nicely should keep them nice clean and fresh"
Answered on 10th Jun 2024 - Member since Nov 2023 - report
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