Tomato sauce combines pigment, oil, and sometimes protein, so remove excess, rinse from the back, and pretreat before washing. Dryer heat can make any remaining discoloration harder to remove.
Lift excess sauce without spreading it
Use a spoon or dull edge to lift sauce from the surface. Do not rub outward from the center because that can drive pigment and grease deeper between the fibers.
Rinse with cold water from the back
Place the stain face down and let cold water run through the fabric from the back to push residue out. Very hot water at the start can complicate sauces that also contain protein.
Pretreat both grease and pigment
Apply liquid laundry detergent or a compatible stain remover, let it work for the directed time, and rub very gently if the care label allows. On suitable whites, oxygen bleach may help when used as directed.
Do not machine-dry until the stain is gone
Wash according to the care label and inspect the damp garment in good light. If a shadow remains, repeat treatment before machine drying because heat can make the remaining stain more persistent.
Sources
- American Cleaning Institute — Laundry Basics — Household laundry, dosing, stain treatment, and fabric care according to care labels.