How do you tell in laws not to give you or your hubby their junk?

My hubby has a mild hoarding habit. He’s already got a basement full of useless shit. whenever someone (anyone) offers him more shit (dishes, clothing etc) he feels obligated to take it even if we don’t need it. My in laws are aware of this and continue to offer us and give us their shit - even me. And it’s nothing we absolutely need. Ever. It’s just “stuff” they don’t wanna do away with themselves. Old clothing, old binders, knick knacks.

They [b]know[/b] I am a clutter manager around here. I politely decline and in a round about way remind them that I am working to manage possessions we already have (which again, they already know because they think hubby is “sick” based on his hoarding habits) I don’t wanna seem ungrateful but I don’t want your clutter!