By Ariane Sohrabi-Shiraz For those who use their microwaves daily, they know how quickly grease and grime can build up on the appliance – and how annoying it is to clean. No one wants to spend a fortune on cleaning products, especially when you could just make a simple solution at home that will cost you under £1. The microwave is one of those appliances many people tend to leave quite a while before cleaning, which can result in a pretty nasty build-up of dirt. But luckily, a savvy cleaner has shared the hack she uses that leaves her appliance sparkling clean every time – and it only costs £1…