6. Tomato, curry and grass: pigment stains with different weaknesses
The last group are strongly coloured plant pigments, and each has a specific weakness worth knowing.
Tomato is both acidic and pigmented, and it responds to cold flushing followed by dish soap, then an oxygen bleach soak. Do not use hot water at the start, which sets the pigment. Sunlight helps enormously afterwards: lay the damp item outside and the remaining pink fades noticeably within a couple of hours.
Curry and turmeric are the hardest stain in an ordinary kitchen, because curcumin is a powerful dye and it turns red when it meets alkali — which is why bicarbonate of soda appears to make a curry stain dramatically worse before it gets better. Flush with cold water, treat with dish soap, wash with biological detergent, then put the item in direct sunlight while still damp. Ultraviolet light breaks curcumin down better than any product, and a yellow mark that survived two washes will often vanish over a sunny afternoon. An oxygen bleach soak helps on whites; on plastic containers stained by curry, sunlight is again the only reliable fix.
Grass is a combination of chlorophyll, protein and sap, so it needs a two-pronged approach. Work neat biological liquid detergent into the mark and leave twenty minutes, then dab with isopropyl alcohol on a cloth for the chlorophyll, then wash warm. Skip the alcohol on delicate colours.
Three rules apply to every stain on this page and are worth more than any individual product. Work from the outside of the stain inward, so you never expand its edge. Always air-dry and inspect before the tumble dryer, because heat is the step that converts a treatable mark into a permanent one. And if the first treatment fails, repeat the same treatment once more before escalating to something harsher — most reported failures are a single attempt on an old stain that simply needed a second pass.
Finally, know when to stop. Silk, wool, viscose, leather, suede, and anything labelled dry clean only should go to a professional with the stain identified out loud, ideally untouched. Telling the cleaner what caused it is worth more than anything you can do at the sink, and a home attempt that has already set the mark usually removes their best option too.