i've never felt the need to 'detox' from weed before tripping, although i only smoke 1 or 2 times a week these days. i actually really enjoy mixing lower amounts of changa and weed, but only if i smoke the weed after i've had a bit of changa already (after that i can mix it)..it kills the potential anxiety i might get from the cannabis when i do it this way
i can see why some would like to be clean of weed for a bit though before tripping if they're addicted/abusing it (not saying you are, just that its what i've observed)
detoxing though can be very powerful. juice feasting in particular before a trip has been really nice
<Ringworm>hehehe, it's all fun and games till someone loses an "I"