At some point in its existence, the floor was deemed too boring. The terracotta-coloured floor tiles were covered in glue, and carpet squares fixed on top of them. Then many years later these were ripped up and disposed of, leaving an ugly layer of latex adhesive.
We soaked them in solvents and thinners, probably doing major brain damage (you can be the judge) and then got out the pressure washer.
We went through three separate sets of hoses and lance fittings (nothing is manufactured properly these days!) and hundreds of hours later the tiles were back to looking ‘OK’.