Steve Walker wrote:

One of the problems is that the bottles and caps are of different
materials and the recyclers want the former, but not the latter. The
trouble is that when you flatten bottles, they tend to partly spring
back unless the cap is on to keep them collapsed by vacuum. What we
really need is a requirement for the caps and bottles to be of
compatible materials (not necessarily the same materials).

You hear all sorts of rumours about what actually happens to the
contents of recycling bins after it's carted away, the village rag has a
semi-interesting article from someone who took the time to visit ...

http://www.countesthorpe-herald.org/319/mobile/index.html#p=6

e.g. me being "helpful" and flattening plastic bottles and aluminium
tins, turns out to be harmful. Black plastic is definitely not wanted
even if it has a recycling triangle on it, etc.

[you probably want to shield your eyes from Mrs Santa over the page]