Being green and saving cash is a cool thing to do these days, but did you know your gran is probably one of the best people to get top tips from?
Older generations have lived through some really tough times, like World War II, when they had no choice but to save energy and make do with what they had.
Now at least one green gran is sharing her wisdom with kids on the internet!
Barbara Walmsley's mini-videos for the charity Oxfam show how to mend clothes, save energy and even reduce food waste.
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Find out why George and Lucy think Green Grannies know best
She said: "Because we have this enormous choice of food people have forgotten how precious it is and they will throw things away without feeling bad about it.
"When I was a little girl a lot of people sewed and they knitted and they used to sometimes unpick jumpers and use the wool to make something else. It's called Make Do and Mend."
Barbara's grandchildren George and Lucy are already learning loads from her and now Oxfam are hoping loads more people will too.
Charity spokesman Frida Eklund said it's about valuing the things around you and making the most of what you've got.
"Grannies have already been doing this for years," she said. "And not because they want to save the planet, but because it made perfect sense."