An Old Tub: Which Marks Come Out And Which Are The Surface Itself

Check for a refinish first

In older buildings a great many tubs have been re-glazed at some point, and a refinished tub is a thin coating over the original surface rather than the surface itself. Abrasive powder, a scouring pad, or a strong acid takes that coating off in patches, and once it is off it cannot be spot repaired.

The signs are visible if you look. A slightly plastic look to the finish, a paint edge where the coating stops short of the overflow plate or the drain flange, small chips showing a different colour underneath, or an area that has gone dull and slightly rough while the rest is smooth. If any of that is there, treat the tub as painted rather than as porcelain, and it is a fair thing to ask the building about before you clean it.

Three things that look like one stain

• A greasy film across the whole tub, from soap and body oils. It feels slightly slick and it comes off with dish soap.
• A ring at the water line, which is that film plus mineral, and needs both steps.
• Mineral deposit, chalky and often worse under the tap and around the drain, which needs an acid rather than a detergent.
• An overall yellow or cream cast on an old white tub, which is usually the surface having lost its gloss over decades.
• Fine grey lines that will not lift, which are scratches from years of abrasive cleaning by previous residents.
• Rust-coloured marks, which are their own category with their own cause and are not stains in the tub at all.

The one-minute test: wash a small area properly with dish soap and look at it wet and again once dry. What improves is dirt. What looks identical after a genuine attempt is the surface.

The order that works

Dish soap and hot water first, over the whole tub, which removes the film and stops it interfering with everything after. Then white vinegar for the mineral part: a cloth or paper towel soaked and laid against the ring for fifteen minutes does more than any amount of scrubbing, because dwell time is what breaks the deposit down.

Then a paste of baking soda and a little water on whatever is left, spread and given twenty minutes before being worked with a soft cloth or a nylon brush. Rinse fully at the end, since baking soda left to dry leaves its own white film.

The non-slip bottom is the hardest part

Most tubs have a textured area moulded into the base, and the texture holds soap film and dirt in a way the smooth sides do not. A cloth passes straight over it without reaching into the pattern.

What works is a paste left on it for longer than you would elsewhere, then a soft nylon brush worked in small circles, then a thorough rinse. What does not work is more pressure. On a refinished tub this area is also the first place the coating wears, so it deserves the gentlest treatment in the room rather than the hardest.

What to keep away from an old tub

• Scouring powder and any pad that feels rough, on a refinished surface always and on old enamel by preference.
• Bleach as a first move. It lightens some marks, does nothing to mineral, and can yellow a refinished coating.
• Drain cleaner poured into a tub and left standing, which attacks the surface as well as the blockage.
• Anything acidic left overnight rather than for minutes, since long contact damages enamel and coatings both.
• A bath mat with suction cups left in place permanently, which traps water and marks the surface underneath.
• Mixing products. Bleach and acid together produce a gas, and in a small bathroom that matters.

Where the tub is simply old

A tub that has lost its gloss, has fine scratching across the base, or has a permanent cast to it is worn rather than dirty, and no product reverses it. Refinishing does, but that is work for the building rather than for a resident, and doing it yourself in a rental creates a problem instead of solving one.

In a rental the useful move is to photograph it early with the date, so its condition is on record as something you inherited. That takes a minute and settles a conversation that otherwise happens at the end of the tenancy with nothing to point at.

The bathroom line by line is in the cleaning checklist, buildup that has had years to set belongs to deep apartment cleaning, and the end of tenancy version is move-out apartment cleaning.