I finished my old bottle of detergent, and was going to get a new one. So, I rinsed out the bottle, and put it in the plastic recycle, and went to Seiyu.
Yeah, it is Japan, so they have ways to reduce the trash, like buying a bag of detergent. I took the old bottle out of the recycle, and filled it up with detergent. The refill bags are generally a little bit cheaper than the bottles as well, but the reduction in trash is enough for me.
Not that I really care about the planet, I just hate dealing with the trash.