Tommee Tippee electric steam steriliser - black dots on plate?

[cantthinkofaname2021]

Hello! Has anyone had this?
So I only used it 3 times and put it away, however I just got it out last night to clean and descale to give to someone - I left vinegar in overnight as it says to on the instructions and I've just gone to wipe it and run a cycle but there's black dots on the plate that won't come off! Has anyone had this?

Not used one but hopefully this will bump for you.

Mine looks like this and it doesn’t seem to be sterilising properly either. I’m EBF and I only need it for my pump so I’m just going to get rid and use Milton tablets. Mine is old so I assumed it had had its day or something!