Red Wine, Baking Soda, and a Wool Rug on Oak
An 8-foot by 10-foot hand-knotted wool rug sits in a dining room over oak hardwood. At 9 p.m. a guest knocks over a glass of red wine; the homeowner blots, then applies baking soda, white vinegar, and a pet-stain enzyme product. By the time you arrive 14 hours later, the spill area is still damp, a white towel pressed on it picks up red dye, and a faint brown tide mark surrounds the spot. The homeowner wants the rug cleaned before a dinner party in 30 hours and asks you to 'use bleach if you have to.' The rug has a dark red border and a cream field; there is no spare matching wool. You have a spotting kit, a wet/dry vacuum, a low-moisture machine, and a moisture meter. The oak floor is finished and cannot tolerate standing water. The homeowner refuses off-site cleaning.
1. Evaluate the homeowner's three products and their likely effect on the wool and the stain. What pH and moisture conditions are you now dealing with?
Read the worked answer
Baking soda is mildly alkaline, around pH 8.3; on wool it can swell the fiber, dull the hand, and contribute to yellowing, especially if left damp. White vinegar is acidic, around pH 2.5; it can affect acid-sensitive dyes and, mixed with baking soda, neutralizes into salt and water with carbon dioxide, so the two largely cancel each other. The pet-stain enzyme product adds surfactants, preservatives, and enzymes; it may be effective on protein stains but needs dwell time and leaves residue.
Fourteen hours of dampness is the bigger problem: the wool and the jute or cotton backing can wick dye, create a tide mark, and support odor. The white towel picking up red dye tells me the border or field dye is not colorfast to water. I would pH-test the damp area, check for residue, and treat the situation as a dye-bleed risk rather than a simple wine stain. No chlorine bleach.
2. What tests would you run before any spotting, and what would make you stop and refer the rug?
Read the worked answer
First, identify the face and backing and confirm wool; then do a wet crock test with a white towel on an inconspicuous corner, separately on the cream field and the red border. If color transfers, aqueous cleaning is off the table. pH-test the spill and the residue; test any spotting agent on a hidden wool yarn and on the border. Check for pile distortion, shrinkage, and whether the tide mark is old. I would also test the oak finish for water sensitivity before placing anything on the floor.
I would stop and refer to a rug plant if the border bleeds heavily, if the stain has already bonded as a dye stain and the customer wants full removal, if there is backing separation or odor, or if the rug cannot be dried flat within the deadline. A borderline crock test means only dry-side or very low-moisture work, with a signed risk acceptance.
3. Assuming the dye test is borderline, propose a spot-treatment and drying plan that protects the oak floor and the customer's deadline, and explain what you will tell the customer about permanent staining.
Read the worked answer
With borderline dye fastness, I would not flood the rug. I would set a plastic sheet and absorbent pads under the rug, work from the outside of the spot inward, and use a dry solvent or a tested low-moisture spotting agent on a towel, blotting rather than rubbing. If a reducing agent is considered for the wine dye, it must be tested on a hidden wool yarn and on the border first; chlorine bleach is never appropriate. Extract only what I apply, weight the area with white towels, and dry with air movers and a dehumidifier, keeping the oak floor dry. I would schedule the work early enough to allow 24 hours of drying before the party.
I would tell the customer that the wine is a dye stain, that the previous baking soda, vinegar, and enzyme mix and the 14-hour dwell reduce the chance of complete removal, and that the tide mark may remain or lighten but not disappear. I would put that in writing before starting.