I use shampoo from a large bottle with a pump. The pump can’t get the last bit out of the bottle.
I cut apart the pumps from two shampoo bottles and epoxied the caps together to make an adapter. I’m going to use it to attach the old bottle to the new bottle and drain the remainder out.
I 3D printed this funnel for that same purpose. I have been patiently waiting for an opportunity to use it.
A few years ago I designed an adapter, but then my 3D printer died and I never bothered.
that’s not dull enough. Take it outside, tech boy.