Non hazardous micropipette tips can be collected for recycling. Collect in a puncture proof container. BL1 and BL2 tips must be decontaminated with bleach or alcohol before being deposited into a recycling bin. Pharmaceutical contamination would also prevent recycling of tips.
Always check with the environmental, health and safety office at your institution first. Sometimes finding a pipette tip inside a recycling collection container will automatically make everything considered "trash". Your institution recycling program rules will be dependent on EPA, OSHA, local hazardous waste regulations, and the municipal recycling services that are available.
Once you have a pipette tip recycling system cleared to start, its easy!