We've tried to make the most environmentally friendly NFC cards possible. Silver ink is used to print the antenna and MOO NFC chips are not made of PET but of silicon. Also, the amount of ink used is very small, and therefore the ink will be removed via the “standard” ink removal system in recycling.
MOO NFC chips have the density of silicon (2.5 vs water), thus is will be also removed easily during the recycling of paper.
So, we're pretty proud to say, compared to standard plastic metallic foil NFC chips, we are very eco-friendly.
Typically NFC chips use aluminium etching of plastic tags which is done using “bad” chemicals and removing plastic from paper is pretty difficult during recycling.
If you are going to throw them away (and we hope you don't!), you can dispose of them via normal trash or paper recycling.