That’s clever, but pine sap can leach stuff into the water and the coffee mug might crack and release metal. Try a two‑stage filter: first, a clean cloth or coffee filter to catch debris, then a ceramic or charcoal filter—cheap ones are easy to find or even DIY with an old jar and activated carbon from a gas station. If you’re tight on cash, a clean plastic bottle cut in half works as a makeshift strain. Just make sure whatever you use is food‑grade and you rinse it well before use. Stay safe and budget‑friendly.