My grandparents and my father are always trying to give me worthless junk. Sometimes they even buy this crap … somewhere for me if it is on sale. I never ask for it, they just go out and buy it for some reason. I have never been a football fan, but I have hats for the Patriots, Lions, Bears, Packers, and Jets. My closet is always overflowing with clothes that one of them bought on sale, I have so many I haven’t been able to even keep track of them all for years. My grandmother even offers me lots of stuff that should have been thrown out decades ago! She often says things like “Do you want your aunt’s old alarm clock? It hasn’t worked since 1981.” She also thinks everything is a collector’s item. She once said I could have a torn-up dog leash to sell on ebay, because she thought it would be a collector’s item just because it was manufactured in West Germany. Also, expired foods. She used to try for a while to get me to take this half-full box of garlic salt that she bought back when President Nixon was in office! It had turned into a solid rock. If I want garlic salt, I’ll buy some fresh stuff, not use a 40 year old brick. I eventually made her throw it out. How do I politely get them to stop offering me this stuff? I do love my family, but I only have so much storage space, which I don’t want to use on keeping things that I either have no use for, or should have been thrown away 30 years ago.
I just take it, then every couple of years I rent a dumpster.
Have you tried saying to them: “Stop pawning off useless crap on me”?
Ask them to give you some paragraph breaks the next time they want to give you something. 
Seriously, if you don’t have the balls to tell them stop, you have to throw the worthless stuff away and give anything to charity that can be given to charity.
Or, you could try Antique Roadshow. Maybe that alarm clock is worth $500,000!
Say no.
Or say “thank you. Good Will can use this. I’ll take it over this weekend.”
My family does the same btw. Raised by Great Depression parents. Everything, somehow must have a purpose. And if they don’t want it, they want to “home” it in the family.
We give all our useless crap to a local woman who holds garage sales every other month, with all proceeds benefitting a local shelter. She gives me a receipt for the items I give, and it helps with taxes. (I think she’s supposed to wait till items sell, not give me a receipt for her estimate of an item’s value. But, hey, IANAA.)
My mother-in-law got to a point with Christmas presents where she declared “Stop buying nick-knacks! I have no more room for bud vases and picture frames. You have two options: whiskey and chocolate.”
(And while we did get a little more creative than just two options, the family mostly complied. All except the one granddaughter who believes its her life’s mission to give framed pictures of her children to every human on the planet.)
If people don’t take the hint though, I see nothing wrong with tossing the trash and donating the rest to charity.
An accountant with whom I worked gave me this advice: take everything anyone offers you, donate it to charity, then take the tax deduction.
So you can hang it on your family picture wall in the bathroom.
(I’ve never understood either one.)
If you’re in the US, the tax receipt should confirm only the date and the nonprofit’s information (name, address, EIN). The nonprofit is not supposed to value the items for you; those in the know will refuse.
The value you claim on the taxes is based *your *estimate of the items’ fair market value (or your cost basis, whichever is less, but in a gift transaction, your basis is the lesser of fair market value or the buyer’s basis, whichever is less, so you’re probably safe).
The nonprofit’s actual sale value is mainly important for motor vehicles. If the value of a motor vehicle is more than $500, then 1098-C will be used to tell you how much you can claim.
This is how they say “I love you”. You can make them stop, but you must give them an alternate way to express affection that is meaningful to them. Or, just take the crap, and remember sometimes garlic salt is a hug.
I would take the stuff, say thank you, and trash it or donate it myself.
I also like dracoi’s MIL’s ultimatum of “whiskey or chocolate”!
My nice grandma (not to be confused with the spawn of devil granny) belonged to one of those music-of-the-month clubs (you youngsters have no idea what you missed out on), and she kept gifting her picks-of-the-month to me because she couldn’t figure out how to cancel them. “Best of the Statler Brothers” 8-track, anyone?
I accepted them graciously, then gave them away.
I sure wish she was still around to give me useless crap. 
No hoarder will let you throw away anything that could be worth something to someone. Clearly tell them that you don’t share their illness and giving you junk = throwing it away.
My grandparents are downsizing, and my grandmother has been trying to give me useless junk for a while. I just tell her no, and she mostly gets the hint. I think it really struck home when I told her that when she died, we were going to burn down her house for the insurance money rather than try to clean it out (as a joke, but still). She’s the cool grandma though, I wouldn’t feel comfortable telling that to all of my relatives.
This.
As long as you let people know you might not keep everything. Be out open with family about what you do.
Maybe if they think you are ‘throwing stuff away’ you won’t receive so much stuff.
Or you keep donating stuff for a tax write off.
Or have a nice big yard sale. You would be amazed at the crap that sells. Really you might make a lot or you might make enough for dinner out that night.
I just say “no thanks” or (and I actually do say this) “no thanks, I have a rule that I won’t take something out of someone’s basement just to put it in my basement”.
Now, don’t get me wrong, if your grandma is a million years old and she’s not going to be doing this for too much longer (and not going to be at your house to see this stuff) just take the ‘gifts’ and when you get home just toss them before they even make them into your house. She’s happy, you made her happy. Why annoy her over something like this?
Of course, if it’s your dad, you need to say “no dad, just throw it out, I don’t want it” or “No thanks dad, either you can throw it out or I can throw it out for you, but I don’t need it”.
My grandfather tried to give a lawn mower to my dad. “I’m 55 years old, I’ve owned this house for 25 years, and the neighbors would have complained if I hadn’t been cutting the lawn during that time”
Just donate it to a thrift store. Why do people think getting unwanted gifts is such a burden? Someone else can probably get some use out of at least the clothes. Throw away the expired food, of course.