Hi,

I'm currently restoring a Nuova Simonelli Oscar which I bought online. After testing that all the major parts are working, I started to disassemble it for cleaning. After taking out the boiler I started draining it and to my surprise that the water was really blue (see photo). I then removed the fittings and lastly the heating element. I was shocked to see that the heating element was totally covered in blue scale I checked boiler and there was also the blue residue inside.





Based on the seller, the machine was used in a bed and breakfast establishment before he bought it and It was not working properly when he got it and had it repaired. From the service invoice a lot of parts was replaced and that it was descaled and flushed. Just don't know if the boiler was descaled as well.

I haven't tried to descale or remove the build up yet. Just want to know first what the blue stuff is and if its toxic? And what the best way to remove it. Should I scrape it off first then descale or should just go straight on descaling? BTW, the blue residue is powdery and can be easily scrape off.

Thanks!

I doubt it is copper sulfate, one blue compound that comes to mind. poisonous, it is.