Permanent ink pens are a popular choice since the ink doesn’t smudge when you make notes or sketch out ideas. But the plastic casing for indelible ink pens are hard to recycle and most likely will be thrown in the trash when the ink is gone. If you can’t live without permanent ink pens, look for newly designed stainless steel pens that are also refillable. When it’s time to replace the ink, you simply replace the cartridge and reuse the metal case. And if you ever need to recycle the pen, the stainless steel case can be easily tossed into the recycling bin.