yes
like burning cocaine, depending on what nastiness it may have been "cut" with.
Sounds like your heater has dust bunnies and needs a good cleaning, when dust or fluff heats up it starts to singe or burn causing the burning smell.
Its just the wax they have on them to stop them from rusting while in storage
pollution or Bactria or that it's been sitting still for about 2 days
There would have been a strong smell of burning, smoke and dust.
No, they do not. If you smell ammonia it is not coming from the heater unless something has been put inside the heater and is burning.
cut in half a load of lemons put them in close the door and leave a couple of days
If the car is a manual and you are riding or slipping the clutch it could be that. Otherwise if you have been real hard on the brakes lately they can create quite a smell aswell.
If you have ever smelled laundry bleach, or been in a swimming pool and noticed a smell to the water- that is the smell of chlorine (in a fairly mild form). Pure chlorine gas is pale green, has a choking, burning smell, and is deadly to breathe. Whether it is "worse" than the smell of wastewater would depend on the purity of the chlorine you smell- the more pure, the worse the smell.
If you smell wires burning, most likely that is the exact problem. If two wires were to melt together it would short the battery and kill it very easily.
Gasket is leaking oil. Valve cover gasket is likely suspect.
Use your judgement. Look at it, smell it, taste it . If you have any doubts discard it.