Yes, I know the lad has a learning/mental disability, and that's why he's supposed to be here every Friday to do a little job, to help him learn the routine and discipline of work now that he's old enough to leave school. So it's not surprising that he can't remember the routine from week to week.
However, you're the carer, you're supposed to be keeping him working and doing it right. I typed out a nice clear set of instructions on how to sort the recycling, and what things we reject as rubbish. We even dug out some magnets so that you could separate steel from ali (which we do by experience).
So why don't you bother to read the instructions and use the magnets?
It took me 20 minutes to day to resort the boxes of stuff, chuck out the rubbish, and generally get it right.
The worse thing is that when we got back and you were already working, you'd been chucking stuff straight into the skips instead of leaving the boxes for us to count, so god knows what contamination you've already caused.
It's bloody annoying. We do a good job and take pride in it, but you clearly think it's beneath you and doesn't matter. Not to mention, you're hardly helping the lad learn anything about doing a job properly!