The problem is that most of the heat transfer in an oven is radiant, so a transparent liquid in a transparent dish is going to get very little heat transfer. Though the air is transparent as well, it need much less heat to get to temperature than water does. One option is to use a non-transparent dish.
The emergency treatment of polycythemia (e.g., in hyperviscosity or thrombosis) is by venesection, the removal of blood from the circulation. Depending on the underlying cause, venesection may also be used on a regular basis to reduce the red blood cell count.
Polycythemia vera (pol-e-sy-THEE-me-uh VEER-uh) is a slow-growing blood cancer in which your bone marrow makes too many red blood cells. These excess cells thicken your blood, slowing its flow. They also cause complications, such as blood clots, which can lead to a heart attack or stroke.