In this weeks video I look at the best way to clean a headliner. Is a soapy solution from washing powder better than a dedicated foam upholstery cleaner?
Both seem to clean equally well.
The benefit of the water solution is cost and cost only. It is much cheaper.
However the foam cleaner is much cleaner, no dripping water to deal with. The foam cleaner is probably less likely to cause damage (because it has no water) and generally it is much easier to apply.
In short, unless the 5 euro cost of a can of foam cleaner is a big issue, I’d go with the foam upholstery cleaner every day of the week.