Very few (if any) pump bottles give you all of the contents that the bottle contains - There is almost always some left at the bottom. The "straw" is too short or doesn't reach the corner at the bottom. Anyway, this set of funnels allows you to stack and gravity-drain the old bottle's contents into the new bottle without (hopefully) spilling a drop. The funnels are named according to the inside and outside diameters (in millimeters) of the bottles, and you use the one closest to your bottle's dimensions. Just screw off the pump on both, put the funnel inside the opening of the nearly-full bottle, and put the nearly-empty bottle upside down into the top of the funnel. Then let gravity do its thing. Thicker soaps or creams will take longer of course, but nearly all of the contents will flow into the lower bottle. Make sure before you start that there is enough room in the new bottle for the top-up, just saying ...
There are three funnels at the moment, and I will add more, so please suggest sizes that you may need. Best regards!