How do you get a stain out of terrazzo?

Find out what the stain is first, because the wrong product makes it permanent. Acid on a cement matrix dissolves the surface — it is not a stain, it is a loss, and no polish restores it. On a sealed floor most marks come off with neutral detergent; what does not come off is usually pigment that has entered a matrix which was never sealed.

Reference photograph of a terrazzo surface, s57. Not a photograph of our goods. — Grey matrix with black and white chips

Reference photographs. They show the material and the finish; they are not photographs of goods we made, and the colour on screen is not a colour-match.

The figures, and where each one comes from

What the mark is	What to do
Dirt and ordinary soil	neutral pH detergent and water
Oil on an unsealed matrix	a poultice drawn over it, then seal
An acid-etched area	⛔ not removable. Ground back, which is a different job
Paint	mechanical removal, then seal; mind the joint lines
An epoxy floor	solvent-free method; a resin will haze

Why the processes are not interchangeable

The distinction that matters is whether the mark is in the sealer or in the cement under it. A cement terrazzo is graded stone in a matrix that absorbs, so an unsealed floor takes pigment into the matrix and it stays there; a sealed one does not, which is why the sealer is maintenance rather than decoration. The case that cannot be undone is an acid. Acid does not sit on a cement surface, it reacts with it, so the dull patch is a chemically thinned layer — and a stronger product used on it removes more. The instinct to escalate is the thing that turns a mark into a floor that has to be ground.

What these figures are, and what they are not

This page describes materials and what they do with chemicals. ⛔ We give no product, concentration or dwell time and we do not sell a cleaning product; ⛔ send a photograph before you buy anything and we will tell you which of the two situations you have — a mark that can be cleaned, or one that needs grinding.

Measured data sheets and test reports

If you are specifying this

These are the forms we actually supply for this question, with production photographs where we have them:

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