THIS!!
I want to know about this as well, as im in the EXACT same situation.
Stay Safe
Only one way to find out . . .
Well i found out.
Backstory:
Bought the changa at a festival in germany in 2013. Me and a friend rolled a joint with approx. 0.1g of changa mixed with weed. Didnt feel anything.
Put the changa away back home and kinda forgot about it. Went to a festival summer of 2014 and tried a few hits from some random dudes changa joint. Didnt feel anything.
Went to India in 2015 and was offered a few joint hits here and there on my journey. Never felt it.
For a long period i have been telling my 2 best friends and fellow psychonauts that we should administer the changa through a bong. Invited them over last friday and had a great meal, a few joints and a great evening. I had more or less decided that today was the day for me no matter what. None of my friends felt like tripping that night tho. So after they had left i knew that it was time.
I killed all the lights in the apartment and lit a single candle in the living room. Put on some of my favorite ambient music and loaded the bong with approximately 0.1g of changa.
I carefully dabbed the flame into the cone and thick smoke started to develop. I inhaled the entire cone and BOOM!!!!!!!!!
I blast off into hyperspace. Before i could put down the bong or even exhale my vision was already full of colors and patterns. Got a bit scared but only for a second. Took me by surprise. I cant even remember my head touching the pillow on the couch and i was gone. I think i may have been out for a few minutes with complete ego loss. Time, space and ego totally disintegrated and when i regained a slight idea of who i were i found myself rubbing the couch violently to assure myself that it was real and that it was my "usual" dimension id had remotely returned to.
All my senses was sending morphed signals of sound, sight and touch etc to my brain. Felt the need for water so i staggered to the kitchen and poured a glass.Had to turn the lights as the darkness didnt feel right. Everything still spinning. Went back the couch and got immersed again for a few minutes. I feel it practically impossible to describe my experience, but the colors and visions i saw was beautiful. Whole journey lasted about 15-20 minutes and felt sane again after 40 minutes. After about an hour i felt a strong sexual feeling. Not in a "dirty" way, but in a almost romantic way. Unfortunately i was alone and just enjoyed the comedown listening to music and relaxing.
So yea.
Changa still works even after years of storage.
Stay Safe