Cat putting STUFF in the litter box when done (not cat stuff)

Mew will use the litter box and instead of covering it,she brings OUR stuff (toys, socks,paper...whatever she can find... she has gone so far to find an empty black garbage bag!!) and tries to bury it! Every single time. We have changed boxes, litters... I just don't understand her. If nothing is close by, she will go looking for something.

Any thoughts? We got her at 5 weeks old. I can't remember if she was litter trained or not. We are constantly pulling and cleaning stuff out of the box. No other cat does this. I amgetting tired of pulling "stuff" out of the box.

I told my husband if anyone would know, you guys would.

I wonder if she is feeling insecure.  The litter box is a safe place.  Do you have other cats?  You might try a feliway diffuser or some Rescue remedy or Composure treats or liquid to see if it will help her feel more secure.  You also might want to call and chat with your vet to see if he/she feels it would warrant a vet visit.

Thanks @ShadowCat. We have 3 other cats. Her and two others we got at the same time. Wally we got a month plus later.
Where would I find the spray and diffuser? Do they say for pets? Do I spray her or the box?
I really appreciate the help. This board has been wonderful in helping me.

She seems unstressed and in excellent health. It is just kicking or bringing stuff into the litter box.
Her BEST buddy is our dog. She plays with the other cats... chase, but she and Louie the dog get rough (and they both love it!).
She cuddles with the other cats (cat pile!) But generally sleeps on or very close to Louie. They are so cute to watch. Silly I know.
FUNNY THING is she was raised with a big dog (up to 5 weeks old, not sure you would have anything to do with other animals) and didn't have anything to with Louie until she was 4 months or older. She is 8 or 9 months old now. She is fixed.

My cats do this sometimes too, but not every time. They really like to pull the cat liner up and cover the litter with it, or pull papers from the floor to cover. I don't know the answer, but what I've been doing is putting more litter in so it's deeper. Then they can really dig and get a big mountain over their poop. They seem to like that. 

You can find the feliway on Amazon. I prefer the diffuser you plug in the wall like a glade plug in. 

R rlavach
I have a spray can we got wit h a "jacket" I don't know how to do the spray. The coat would be way too big. I don't I want her totally avoiding the literbox. So I would like to try the spray first but I want to do it right. I don't need cat tinkle outside the box.

A while back... someone mentioned using a deep plastic box you you use to store stuff in. I wonder if the box isn't deep enough or long enough even then what we have. She is a long legged cat.
I still don't understand pulling stuff in, but maybe I will try one of those super deep / long boxes. I totally forgot about reading about those boxes until now. Can't hurt trying plus add another potty box.


Thanks R rlavach and @ShadowCat!

I have 2 litter boxes for my 2 indoor boys.  Two of the boxes are the sterlite containers.  They are like under the bed storage boxes.  They are about 24 inches long and 17 inches wide and 5 inches deep.  It's best to keep the litter really deep. 

I use both Feliway spray and Feliway plugins.  If you have an outlet near the box, the plug in is best.  If not the spray will work, but you may need to respray the area a few times each day.  The spray does not go on the cat, but instead on the area around the litter box.  You can find them both on Amazon or some pet stores.