I wonder if any of you are in a position to advise me in my current predicament?

I conducted the application of castor sugar onto Lascaux soft ground, as described in the recently published "Intaglio" book, by Carol Robertson and Robert Adams. I did this on an aluminium plate.

I then saline etched and proofed it. OK that was fine. I then thought I would do another castor sugar application, to improve the 'aquatint' like affect.

I have been obtaining my Lascaux A.R.E. printmaking materials (sole suppliers of the full range -i within the UK). Unfortunately they didn't have any Lascaux remover in stock so I then ordered some of the Mystrol cleaner as recommended in the book.
I wondered if this might be more economical too, given that I had just spent nearly £200-00, on purchasing most of their range of acrylic resist etch and tusche materials.

But it hasn't worked. I soaked it for half an hour following the directions in the book. But it didn't 'budge" - anyway so then I thought I would leave it in overnight which I did and still nothing !!

Is it the case that if I had the Lascaux soft ground on copper - that it would remove it?

Perhaps it doesn't work with aluminium. I had also read somewhere that using sodium metasilicate crystals would remove acrylic resist - but again I followed the instructions and it did not remove the resist.
I wish I was more knowledgeable where chemistry was concerned !!

Aine