Middle grade book--kids with a magic box

My friend read this in the mid-'80s, checked out of the elementary school library. It could have been older. It was about a group of kids--at least two, a boy and a girl, possibly more--who find a box. Either they open it and things come out, or maybe they put things into it, but most of the book is a series of stories. Each chapter is a story about something magic that happens as a result of their interacting with the box.

It's definitely not Half Magic. She's looked at Edward Eager and it doesn't seem to be anything by him. Any ideas?

The Ogre Downstairs by Diana Wynne Jones?
A step-family's children are given a box of magic chemicals each by the man.Two boys are his, two boys and a girl are hers)
The chemicals cause all sorts of weird things to happen.
'Casper, Johnny and Gwinny get a big shock when their mother marries the Ogre. The Ogre is large and stern and not at all interested in children, although this doesn't prevent him from adding his own two awful sons, Douglas and Malcolm, to the family mix. Now the five children and two adults are squashed under the same roof, which can lead to only one thing – war!

Then the Ogre brings home the Chemistry Sets – one for Malcolm and one for Johnny. Not that Johnny is impressed by this very obvious bribe. At least, not until they accidentally discover the flying lotion. Then the real fun begins…'

Maybe Magic in the Alley by Mary Calhoun:

Cleery finds a box with seven magic items in it and even though the magic is soon spent it brings three friends something of value.

At first I thought this might be a book by E. Nesbit, as it sounds similar to her style. However, I couldn't find one that seemed to fit. Her Library Thing page is here if your friend would like to check:

http://www.librarything.com/author/nesbite

Another possibility is The Magic Box by Katie Cleminson. I'm not sure, but think this was published in 2009. If so, it's not the right time frame.

Perhaps "Castle of Bone" by Penelope Farmer? It's about a boy named Hugh and his friends- they find a cupboard that is magic, put things into the cupboard and something different comes out. They put a leather wallet into it and it changes into a pig. They experimented with putting different things inside to try to figure out how the magic worked.

This is great; I'll run these possibilities past my friend. We did consider E. Nesbit but couldn't come up with a book that fit the description. Thanks so much, and I'll let you know if one is the answer!

It looks like Magic in the Alley is the right one. Thanks for your ideas everyone! You should have heard the passionate frustration she used describing the book--she'd been looking for years!

Fantastic, I loved that book!