have you ever cut open a toothpaste tube, a body lotion container, rinsed a shampoo bottle for washing your hair etc.?
All those containers are trashed in billions, but still contain a couple more days of clean teath, soft skin, clean hair or dishes etc. On a global scale, imagine how much this would save, if just everybody did it!

Even more, you should consider to ALWAYS dilute your liquid dishwashing soap with the same amount of water. That way you don’t waste the (usually over-concentrated) soap at all and for the whole container – by accidentially applying too big squirts! This happens so easily and on a daily basis by rushing, not paying attention, by the kids. The pre-diluted soap spreads much better on a (dry) sponge and you will notice how much longer the bottle will last and save in future.
By the way – I banished all body shower and shampoo plastic bottles for good by using a vegetable oil based soap bar and a shampoo bar. This prooved much better for my skin, too, that used to be dry.