How do I get a grease mark off suede without ruining the nap?

Why the usual answer works

Grease is an oily soil, and the two things that shift it are a surfactant that emulsifies it into water or a solvent that dissolves it outright. Both are effective on the grease itself, which is why washing-up liquid and a solvent-dampened cloth are the two things people reach for.

Usually recommended: Detergent, Isopropyl alcohol.

Why it must not be used here

Suede is the porous lower split of the hide with nap on both sides, dyed like aniline and uncoated. The trade guide states that cleaning agents will immediately darken nude leather — there is no cautious first application, because the first application is the result. Water is not a safe alternative either: the guide specifies deionised water because hard water containing minerals may cause rings. And the guide separately prohibits alcohol, strong solvents, high-pH cleaners and dish detergent on leather generally, as incompatible with modern finishes.

This damage cannot be undone by cleaning. There is nothing left on the surface to remove.

More about suede and oil and grease on textile.

What to do instead

Change the mechanism from dissolving to absorbing. The trade guide's instruction is to place cornstarch directly over the affected area and rub gently with a finger until it coagulates with the oil, repeating as necessary. The powder offers a finer, drier pore network than the suede, so the oil moves upward into it and leaves with it — nothing is dissolved and nothing is carried deeper. Only if the mark is still evident after that is a cloth dampened with odourless mineral spirits used, and it is the last step rather than the first. Where water is unavoidable for a water-based soil, the guide specifies dampening rather than soaking a cloth and feathering the edges outward so no boundary forms, using deionised water so no mineral ring is left behind.

• Absorbent powder treatment — Lifting an oily mark out of a porous surface with a powder rather than dissolving it with a liquid. The gentlest route on anything water would ruin.
• Dry soil removal — Taking the loose material away before any liquid touches it. Skipped almost universally, and it is the step that decides whether the rest works.
• Solvent wiping — Dissolving an oily soil and letting the solvent evaporate. The answer where water would leave a mark or cause harm.

This is a case where a specialist is a reasonable answer. Restoring a surface is a different trade from cleaning it, and continuing to try cleaning products on damage generally makes the eventual restoration harder.

The chemistry behind both halves

• Capillary absorption — Liquid moves through a porous material on its own, and it moves outward. It is why a stain grows after you treat it, and why a powder can pull one back out.
• Dye migration and colour bleeding — The colour of the thing you are cleaning can move too. Every trade body that publishes a stain procedure opens by telling you to test for it.
• Solvents and polymers — A solvent cannot tell a soil from a surface made of similar stuff. Most modern surfaces are polymers, which is what makes this the commonest way to ruin one.
• Material compatibility — The reason CleaningHQ answers questions about surfaces rather than about products. The same agent is the right answer and the wrong answer depending on what it lands on.