You cleaned the spot. You got down there with a cloth and something in a spray bottle, you worked at it until the carpet went pale, and it looked finished while it was wet. Two days later there is a shadow in exactly that shape, slightly wider than the original. That is not you having missed a bit.

A cloth only ever reaches the top of the pile. Carpet is not a surface, it is a few thousand fibres standing on a backing, and a spill runs to the bottom of them the way water runs to the bottom of grass. When you wipe, you lift what is near the tips and push the rest sideways and down. Then the carpet dries from the bottom up, and it carries the stain back to the tips with it. The wider shadow is the spill you spread.

This works in the other direction. It puts solution down under pressure so it reaches the backing, agitates at that depth, then pulls the water back up and out into a tank. The removal is the part that matters. Everything else you have tried added liquid and left it there to migrate.

The tank is also the only honest feedback you will get. Carpet lies to you while it is damp. What comes out of a rug you thought was clean is the argument for the whole machine, and it is why people run it a second time on the same square foot.

Here is the limit, and it is the price. This is a hundred and twenty dollars for a job most people have three times a year. If you have no pets, no small children and no carpet you actually worry about, a bottle of spot cleaner is the right answer and this is a machine that will live in a cupboard.

It is also not a carpet cleaner for a whole house. It is a portable, built for a spot, a stair, a car seat, a sofa cushion. Run it wall to wall in a lounge and you will be refilling a small tank for an hour and a half.

And it does not undo damage. Bleach, pet urine that has been down for months, dye from a rug pad: those have changed the fibre. Extraction takes out what is sitting in the carpet, not what has become part of it.