As part of the yearly clean up, service etc I've always spent some time getting the toilet back to the factory finish it was when new. Some forum members will know about the maintenance but I suspect the vast majority do not.
During the seasonal use the toilet cassette gets emptied and rinsed out. After each trip I give it a dose of disinfectant, fill up and leave to soak. But how many of you de-scale the internals. If you remove the cassette, part slide back the flap and rotate the disc mechanism you should be able to remove it. If stubborn an old car number plate acts as a good lever plate instead of the sliding flap. It is a bit stubborn and you need to be careful of the float that points towards the spout end of the cassette.
The first time you do this it would be a good idea to take a few phots to remind you how pieces go together in case you do need to take the innards apart.
You will be "surprised", more like shocked at the innards. Carefully unclip the float and place the disc mechanism in the bottom of a bucket. Rinse out the cassette and pour in about 5L of cold water. Next add 200ml of Kilrock. It is about £10L on ebay, or if a Range is near you the cheapest way to buy it is here. https://www.therange.co.uk/household/cle...r-400ml/#470511 In subsequent years you may only need 100ml. Add a kettle of boiling water, top up with cold water, drop the float in and leave to soak for an hour. When you return, possibly with a scotchbrite type scourer, lightly wipe the inside and you should feel most of the limescale has gone. If not leave another hour and check. When you are happy pour some of the used liquid into the bucket to cover the disc mechanism and leave for 1/2 hour. Check and use an old nailbrush or toothbrush to remove anything that has not fallen off. If need to leave another 1/2hr.
Rinse everything, admire how clean and shiny all is, re-assemble and smile at a job well done.

Colin

I think there are only a few of us who do this job, and it was you who recommended the Kilrock to me many years ago. We must be unique or a bit OCD.

Colin

I notice The Range are selling 400ml bottles for £2.99 so went in search, but we do not have one. I was dragged into B&M and found the 400ml on offer for £1.99. It is not on there website. I love a bargain, seeing I've just blown a wad on a new van, so bought the last 6 bottles. I'll be nearly as old as that Randa bloke by the time I finish using it all up.

Colin