Did you know that paper envelopes with plastic windows are 100 percent recyclable? When waste paper is recycled, the recycling process at the factory takes out the plastic windows and the adhesives on the envelope before the paper is pulped. You can also recycle envelopes from FedEx and UPS that have the plastic sleeve on the front -- no need to remove the sleeve since it will be pulled off at the recycling plant. The one type of envelope you can’t recycle is the kind padded with bubble wrap. Reuse them instead!