Hot water cylinder substance in side?

Hi there plumbers. I'm not a qualified plumber myself although I do reluctantly do it at home. Random query here. I ripped out an old cylinder from my 40s house and replaced everything with a combi (which was done by a certified engineer of course). I've now finished the house so going to do a scrap run as I have a lot of lead and cable and pipework. The cylinders pretty big but has some weird foamy substance in the top. I'm guessing I need to rip this out before taking to the scrappy but wanted to check if there's a chance it might be asbestos. I've done loads of asbestos courses and it doesn't resemble any I've seen. Also wondering how thick this foamy bit is? Cheers in advance.

Ben

 

It is scale (calcium carbonate) because of the heating from the hot cylinder below and probably the remains of the sacrafisal anode which was on the base of the cistern or that bag of food grade phosphate hanging from the open vent.

 

Limescale, dont worry but when you take to the scrappy he will take an axe and split it and tip out all the rest thats in it. They are not stupid and only pay copper prices for copper - thats why they drive Bentleys etc.

 

Great stuff thanks peeps. Can't believe that's just scale. We do have very hard water. Ha ha.