OK, I have my Astra GA opened up for the yearly strip clean. I am a waiting for some parts. This means I have a deep need to really clean everything. Could I safely use CLR on the boiler? Through the copper pipes? If you agree its worth using, how do I make sure its all out and safe? Anything I'm missing?
Thanks
treshell

It's better to use citric acid as your descaler, unless you disassemble the machine and descale it part by part. There's an FAQ thread and some threads on citric acid.

Well if the machine was being descaled as you normally would as part of routine maintenance I'd say no, to use something specifically for descaling. But if the thing is torn down and will be easy to flush everything 100% I'd use CLR without question.

Several years ago I rebuilt an Olympia Cremina for a friend. Had the boiler completely torn down and all I had to soak it in for its size was Lime Away, which is pretty much the same thing as CLR. It not only descaled it very nicely but the long soak also helped to soften and break away all of the "asbestos" insulation on the boiler. But I was able to rinse it very well afterward. Later!