I have read several articles stating that one may double wrap food and place it into a non-kosher oven.
I haven't read anything regarding the "opposite situation". Lets say one has verified that an oven owned by a non-Jew had all non-kosher food double-wrapped. Can a Jew place kosher food that is unwrapped into that oven?
It seems to me that this would be OK, but are there any other possible concerns, here?
The halachot of an oven are much more lenient that one of a dish, since there is no contact between the food and the oven. The real issues are regarding the oven tray which touches the food or dish and transmits taste - and possibly any recent projections of (non-kosher) food on the walls.
As such a clean oven not used for 24 hours, or having undergone pyrolysis (self-cleaning), can be used to cook kosher food if the oven tray is covered (e.g., with aluminium foil).
Your case is even simpler, it is like one of a new oven and there is no issue cooking unwrapped kosher food in there.
Source: I spent the last months learning these halachot with a rosh kollel from Bnei Brak and checked again a similar case last week.
