Egg quite right too - It would really help you if you could get him on board.
Scout how long do you think it would take him to notice?
I would never get rid of anything of dh's which I think might hold sentimental value but there is plenty that I could dispose of that he would never even miss.
As I declutter I have taken to putting the stuff which belongs to dh on his side of the bed or his bedside table. Some of it has stayed there and some of it has found a new home in the bin, my ebay box etc.
Dh's problem is he doesn't value ANYTHING in the house which belongs to someone else and would happily sell it all or sees it as clutter yet he hoards running magazines and University notes from nearly 20 years ago etc.
It is very difficult.