Ruby Wilkinson, nine, and her four-year-old sister Erin have been making the magnets - adorned with rainbows, NHS logos, hearts and Union Jack flags - and pinning them to a board outside their home on Clumber Street.
Inspired by another pair of youngsters, Reenie and Lacey Goldsbrough - featured recently in the Chronicle - the girls have asked passers-by for donations, which will go to Barnsley Hospital.
“We passed the girls’ house and Ruby and Erin wanted to do something similar,” said mum Sally, 34.
“They’re only young, but they’re aware of the situation and have joined in the weekly clap for the NHS.
“They’re loving doing it. They sit by the window and say hello to people who stop outside the house.”
Ruby also joined Sally and some work colleagues recently as they walked 26 miles across six days, raising more than £600 for the hospital.