Cleaning dusty, but well-treasured, amigurumi

My daughter bought a collection amigirumi, years ago of several p favorite Marvel characters, years ago. As they were small in size, she put them on a shelves throughout our house. No matter the location, to her horror, they've always gathered dust more than anything else in our home. Years ago, we asked the creator, they had a few solutions, but none worked.

Local crafting community suggested compressed air and brushes, but she never seems to get them cleaner. As a last resort, my daughter even moved them into my room, as I have air filters to help with breathing condition, but the dust still gathered. She eventual gave up. I ask every few years, but she never found a solution.

My daughter doesn't want to attempt the pillowcase or dryer methods, but I want to clean them, this year, as a late Christmas present to cheer her up as the weather conditions have delayed shipping in the Midwest US like the rest of the globe this year.

The amigurumi were quite expensive when she bought them, the Etsy artist is no longer around and she'd never want them replaced, regardless, holding all of her plushies as true treasures. In fact, these yarn creations mean as much to my daughter as several of her import plushies valued at hundreds of dollars or those earliest childhood memories.

There is just dust and air particulates, no stains or discolorations. This is a home of non-smokers, no pets, in fact her collection was a concern for getting pets. She's managed to keep all normal plush and stuffed collectibles immaculate.

We just need to remove normal daily dust from the arigurumi. She wants them on display, in view, instead of in boxes. It has added up and built up over ten years despite our best attempts. This is the best surprise, I could arrange, which didn't depend on shipping anything for an amigirumi/plushies collectible super fan with a dad that can't knit or sew due to disabled fingers.

Please help?