Badly damaged cactus

[Benyellow]

Ok I have A LOT of questions, so I just brought back this grafted cactus from my friends house (He is not good with cactus) because it's badly damaged and in need of saving. I've cleanse the peat-covered root. So here's the questions:

Is this cactus sunburned? And if so, how should I treat it?

2nd question:
The scion is Astrophytum which naturally have white flecks, but the white flecks appear to be growing on the stock too, so I'm wondering if it's scale?

3rd question:
I'm planning on separating the two cactus, how can I do that? where should I cut? There's little info on how to undo a grafted cactus.

4th question:
Is the bottom cactus savable? It's badly damaged and the stem appear black, the roots are quite ok though.

Pls help, thanks a lot

[cortez753]

Thats not grafted.

[iann]

If the roots really are OK, you can just plant it. Not very pretty though. You might want to chop the bottom half off and re-root.

[Benyellow]

Thanks guys. Woah I didn't consider the not grafted possibility, this is Astrophytum ornatum right? which gets columnar as it ages?

[cactushobbyman]

Only with age, and I find this guy very hard to re-root, at least for me.