No the loose particles might get into the food.

I assume you have gone around the edge with a thin knife to see if its
hardened grot that is the problem?
Seems odd for it to be a screw in type, most of the ones I've seen have
some kind of latching device that pushes pulls or twists.
Brian

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"thescullster" wrote in message
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On 26/04/2021 10:28, Harry Bloomfield wrote:
thescullster expressed precisely :
Does anyone have any words of wisdom on methods to get the glass cover
to unscrew please?
And yes, according to the instruction manual I am turning the thing the
right way (although I have tried "tightening" it in an attempt to free
it off).

Ours are oblong, either side, slide in to latch and yes they too jam. I
get a heavy block of wood and tap them with that, which always frees
them - though next time I intend smearing some high melting point grease
on the mating surfaces, to see if that helps.

Hmmm yes - haven't tried the hammer approach yet.
Surprised no-ones suggested an angle grinder.