You can anneal 6061 with a propane torch. One way to test the temperature is to heat the rod in the region you want to bend and every so often take the flame away and press a piece of pine wood against the hot part. When it is hot enough to char the wood slightly you are hot enough. Now you can quench it in water and it will be soft, or at least a lot softer.
However it is not really possible to get back to the original state. Alluminum alloys do increase in temper with age but at room temperature it is a very slow process. You could try holding it in a cooking oven for several hours at around 350 degrees F and see if it makes a difference.