I notice this question comes up a lot, so I have included some basic info on cleaning Victorian tiles just based on my own experience. However, there are other effective ways to clean these tiles as well. This below can also be applied to old quarry tiles.

1)Alkaline degreasing stage 1

Alkaline degreasing detergent stage: Always start with an alkaline degreasing stripping detergent (except if there are large chunks of screed or cement). Old tiles are quite porous with a lot of grime, past tile sealing products and waxes sitting inside them. Acidic detergents don’t get through all this stuff properly, so we need an alkaline detergent to melt it all first. You can think of these detergents as heavy-duty grease removers you would use in your kitchen. 

These alkaline detergents need to be left a bit to soak and also require agitation with either a stiff brush or coarse scouring pad. Professional cleaning supply outlets have a good selection of brushes more suited to this work than what you would find in the supermarket.

Here are some good professional degreasing alkaline detergents that I can definitely recommend below…

Stone Care Direct Ultra Strip

Fila PS87 Pro

Faber Cottosolv

Tile Master Heavy Duty Extreme

2)Acidic detergent stage 2

Acidic detergent: Now that the grease and grime has been removed, acidic detergents can penetrate deeper into the pores of the tiles for more effective cleaning. These detergents are heavier than water and really deep clean well. Acidic detergents remove cement-screed residue and limescale build-up and will brighten your tiles up nicely. It’s important to rinse properly with clean water between these stages because alkaline and acidic detergents cancel each other out and will be far less effective if not rinsed off before the next stage.

Agitate your acidic detergents with a stiff brush or scouring pad. You may see it fizz as it reacts with cement or screed haze.

A couple of good professional acidic detergents include…

Stone Care Direct Porcelain Pro 

FILA Deterdeck

Faber Disycott

Tile Doctor Acid Gel

Tile Master Cleaner number 4

3)Large chunks of screed or cement on the tiles

You need to use a lot of acidic detergent with a scraper or gentle chiseling first. Keep the floor nice and lubricated with your detergents, which softens the material and helps to prevent you from marking the tiles with your metal tools.  

You can also use wet rated silicone carbide stone sanding discs to help with removing light cement and screed patches on the tiles. Be sure to use appropriate grit, usually 400–600 for Victorian and quarry tiles. ” Sait” silicone carbide discs are good.

4)Carpet glue on the tiles 

Large patches or chunks of glue can sometimes be found on Victorian tiles that have been under carpets. The glue is usually a yellow-green or brownish color and can be quite hard to remove.

To remove this type of glue, it needs to be loosened and melted with a solvent. The best one for this that I know about is “Lithofin Wax” Off. I found a scraper with some Stanley blades, and a small hand-held steamer that really aids in loosening carpet glue.

Once the big visible patches of glue are removed, they commence with stages one and two above.

5) Black bitumen glue  

This was used to fasten vinyl tiles and is quite tricky to get off. Bitumen glue would be best handled by a professional, as it requires proper equipment and experience to remove it without damaging the tiles.

However, as a brief description of cleaning this type of glue, you would be using something like Wax Off solvent to melt it, followed by proper extraction. Once it melts with your solvent, it can sink deeper into the tiles and stain them permanently if not extracted properly, so be very careful!

6) Yacht Varnish

Yacht varnish, or strong polyurethanes can be removed slowly and painfully with a solvent such as Lithofin Wax Off or strong paint strippers. Sometimes it doesn’t come off properly, and you need to repeat the process as many times as it takes.  A small scraper that can hold the Stanley blades helps remove them once softened. Once all visible varnish has been removed, commence with stages one and two above. 

Sometimes I alternate the alkaline detergent and “Wax off” solvent stages as this seems to rinse the “Wax off” properly before going over it again if need be.

7) Neutralising 

It’s important to neutralize acids by going over them with an alkaline detergent. Acids, if not rinsed or neutralized, can continue to degrade the tiles, making them more porous and weakening them. I see this a lot when coming to a job where customers had builders acid clean the tiles a few years before. These tiles always seem more porous and “biscuity” and sometimes struggle to hold a slurry for proper cleaning.

Simply mix a weak solution of your chosen alkaline detergent (from above). Apply the detergent to neutralize the acids and rinse with plenty of clean water afterward.