What To Know Before You Upcycle Those Old Cups From Fast Food Places

As a way to combat the growing amount of global plastic waste, which is estimated at around 360 million metric tons per year, according to Statista, many people have turned to upcycling everyday items like fast-food cups and the cardboard drink holders they're served in. Because let's be honest, that fountain drink you sipped during your 10-minute lunch break can serve more than just that one purpose, right? And yes, it absolutely can.

Repurposing old or unwanted items, like fast-food cups has become a small but sustainable trend. People use them to store paint brushes, organize random screws, or even as refill cups for their weekly McDonald's pit stop (as long as they're washed out each time). But before you start stacking your cabinet with to-go cups, it's important to know that not all materials interact well with these plastic cups. Some liquids can warp or degrade the containers, exposing your items to harsh chemicals or even damaging what you're storing inside. Each type of plastic also reacts differently to varying temperatures and solvents. 

Take PLA (polylactic acid), for example, which is a biodegradable plastic made from plant fibers that's common in fast-food packaging. This normally has the number seven stamped inside the recycle symbol, meaning that the product is compostable (under high temperatures). But, it doesn't always play nice with certain solvents, and if it comes into contact with the wrong one, the cup can break down and ruin whatever's stored inside. Plus, if a cup has already degraded or been exposed to chemicals, it can no longer be recycled, as the liquids or solvents that broke it down could contaminate the entire batch.

When upcycling fast-food cups, it helps to know what material you're working with. McDonald's paper cups, for example, break down if liquids sit in them too long, which can cause leaks or holes. That makes them unsuitable for holding liquids, whether you're repotting your favorite plant or storing brushes after painting. The same goes for PLA plastic cups, which are commonly used for cold beverages at fast-food spots. While PLA is safe for cold drinks, it doesn't hold up well against heat or certain solvents, like nail polish remover (acetone) or alcohol. When exposed, the plastic can break down, become deformed, and potentially damage the items you're storing inside. It could also result in the liquid spreading onto the surface the cup is sitting on. 

For example, if you placed an acetone soaked brush into a PLA cup, it would start to break down the plastic, causing it to become mushy and sticky. If the soaked brush sits for too long, a hole could form, letting the solvent leak through. To avoid any accidents, check the recycling code on the cup to identify the type of plastic it is. This can help you determine how it interacts with certain liquids or solvents. Given this, paper cups from fast food restaurants work best for dry items like screws, buttons, or small craft supplies. Just don't depend on them to hold liquids. As for plastic cups, be mindful of what goes inside, because certain chemicals or fluids can cause damage and speed up degradation.