Is it safe for a isolation transformer to look burnt?

[Nipedley]

Heeeeey guys.. as most of you know by now, previous owner = idiot, and as such he supplied and wired in a nice and black crispy (but working) isolation transformer when he had the machine. I near enough immediately wired it back when I got it, but a week ago I tested it and its still fine (I didnt know it was burnt..) Today I pulled it as im adding the final touches to the machine, and god does this thing weigh a TON! Nearly as much as my 20" Monitor! After I finally got the brute out, I notice it is very black and crispy. The frame is all burnt-looking, the sticker on the side has various black holes in it, the bottom is very crispy and has the residue you get when things burn. All in all, not something I would really trust in my machine. Of course, it isnt going back in there but...
1) Since this is working, I can assume it is *Nearly* dead?
2) Is this thing safe at all?
3) Is it worth anything to anybody?
4) Is it even worth keeping in my drawer for spares?

[Nipedley]

Thanks for the quick reply - Well, as long as it isnt dead/dieing, I'll keep it =). No need for me to order a replacement - I wasnt quite clear, the machine already has its original isolation transformer which is in full fine working order (thats what I wired the machine back too - and why the new isolation transformer was near enough utterly pointless). It is still working fine, I was just worried about the overall burnt look of it - but if its okay, I'll stick it in my spares drawer until such time comes that I need a new one (which I will probably buy anyway) - I rarely ever throw anything out.