I'm going to clean out mum's pantry
Why are you cleaning out her pantry?
I just don't like to think about all the biscuits, cakes and chocolates in the pantry
I understand that it's good to have your house organized. However, you should never throw away someone else's things without permission.
I don't have to ask her if I can do it. I'll do it anyway!
This is your mom's house and her pantry which means that you have no right to clear it out without her say so. I understand that you want things to be organized, but ask her if this is what she wants before jumping into this project.