This can be such a touchy subject - we never want to sound ungrateful or get our children thinking that it is ok to be that way, but as parents, we are allowed to draw the lines on what comes into our homes. There are a few things that I find helpful and that I have worked with over the years.
**Start a few months ahead of big holidays like Christmas and birthdays so you can catch them before they shop. Just gently let them know that you are really working to decrease the toys in your home to help your children not be overwhelmed. Focus on how much this will help the children - try not to focus on how it will help you! Let them know that your focus has become more natural because it is better for them. You can even mention the dangers of plastics if you think this grandparent will listen. Talk about wanting to get back to natural things - appeal to the toys that made this generation happy, simple dolls, wooden blocks, etc. this is very appealing to some grandparents as they remember these things. This sounds a bit like manipulation and I don't like that road, but I do know that there are some grandparents, aunts and uncles that need a gentle hand and won't take well to being blunt, so put on your sweet hat and be sincere and firm.
**Catalogs... long ago, I got the grandmas in our lives subscriptions to places we like to shop. For the grandmas that shop online, I will pop emails to them through the fall and early winter "hey, Sam has his eye on this..." it often sparks a conversation that ends with them putting it on the list for him for the holiday. I like to do this even if they won't be buying, just so they can see what the kids are into and what they really want to play with.
**Be sure that when you go talk to them about your changing values that you don't attack anything that they previously purchased - try to keep it sweet and neutral. Mention that you are weeding out a lot of toys and offer to bring some of them back to their house if they are fussing about you getting rid of things they purchased.
**When they just won't get the message - return items. When my big kids were young, we made a rule about opening gifts at celebrations. The rule came initially from pieces getting lost and children in turn being sad. After the unwrapping, I would ask the kids to only take one thing out of the package so we didn't lose anything. This was a life saver! Then we discreetly put things in the trunk - often they were forgot about and I could exchange them with no trouble. If the kids are big enough to notice, see if you can interest them in what is in the natural section of the toy store. We had a year when our older children were young - in fact, I was still married to my 1st husband - his mother wouldn't get the message, she took it as such an insult that we would even ask her to look at quality over quantity. The boys just really wanted Thomas trains and track, nice wooden trains! She had purchased so many things they didn't want and it showed on their faces (they had asked for trains). As we left the celebration I suggested that we just go exchange the gifts and they were so happy. I let them know that Grandma would want them to have something they enjoyed. They had a nice sum of money to spend on the trains they wanted. I later had a conversation with her - at first she was angry, but I tried to really keep the conversation about the children and what they wanted. The next year she did better and she was greeted with such warm hugs from the children.
This can be such a touchy subject. The children now ask for things like zoo and museum passes, especially the big kids, they want to visit their favorite places even when our budgets are tight. This has been really helpful to us homeschooling. I think often it is about that old saying "you get more flies with honey than you do with vinegar." Be sweet, be understanding. When you get someone that just won't play ball, well then don't fight, I spent too many years fighting and it is just frustration - say thank you, and hide the toy if it is annoying. Be firm but not ugly.
We have a YouTube Playlist to help you through the holidays here.
Family does not understand Waldorf homeschooling? Helpful blog post to send them.
A few Nielsen family favorites:
Acorn Naturalists (more of a homeschool supplier but great books)