[boomboomsubban]

This is an area where recycling probably happens. The ink costs far less than the cartridge, And it's not too hard to make a refillable cartridge.

It's unlikely HP would bother with the envelopes if it wasn't cheaper for them then building new cartridges.

[nerdbert]

If $(perceived PR value of pretending to recycle) - $(envelopes) < $(marginal cost of making cartridges actually recyclable) then you can bet they are going straight in the dumpster.

[boomboomsubban]

This ignores that there are options besides the envelopes.

If they were just going to throw them away, they'd do something like team up with Best Buy to have an cartridge recycling bin available. Most of the PR value at a fraction of the cost.

Actually sending prepaid envelopes means they're probably recycling them.