May be I should open a new thread, but I think my question is complementary with PC2K's one, which seems more a container pb than an esbit pb.
(PC2K : I remember my mother always boiled some milk in new aluminium stew-pans and throw it away (the milk, not the pan !!), before using the pan for real cooking.)

Here it is :

I want to use empty tinned preserve cans as boxes for a few PSKs (I get plastic lids to close the opened cans).

Among other stuff, I will store a few esbit blocks and matches etc... inside, plus 3 flat pieces of metal, that will link together to form a stand for the empty can, so I could boil some water, using the esbit blocks underneath.

Question : is it safe to boil water in a tin can ?
As far as I know, there is some kind of coating (varnish ??) inside the can. Won't this be armful once the can has been heated on the fire ?
<img src="images/graemlins/confused.gif" alt="" />

Any opinion on this ???

TIA

Alain