Hey guys,
I’m currently using 2.6 with Cycles. I’ve pretty much got the hang of it. However I keep getting horrible color spill from objects, even if they have the diffuse material applied.
How do I stop the color spilling onto different objects?! 
You mean color bleeding? That is supposed to happen, it happens in real life too. Go hold a bright-colored piece of paper in the sunlight near a white wall. Notice the colored glow it gives the wall? Honestly, lack of color bleed is a big reason why BI renders look so fake a lot of the time.
test with “No Caustics”