• hazardous material
• biological waste or bio-medical material 
• styrofoam packaging
• over-sized containers,
• degradable plastics,
• multilayer products that have both a plastic and another material in their makeup ( like chip bag aluminium foil), which must be disposed of in the garbage.

The Society of the Plastics Industry, Inc. (SPI) introduced its resin identification coding system in 1988 as a means of helping recyclers identify the resin content of bottles and rigid containers commonly found in the residential waste stream. See the codes here:http://www.bra.org/plastics/symbols.html

Read about plastic pollution: http://www.ecowatch.com/22-facts-about-plastic-pollution-and-10-things-we-can-do-about-it-1881885971.html

Some reuse ideas to extend the life of these items:

• You could buy chair covers (they make them for some styles of plastic chairs) or sew some and use the chairs indoor
• Paint to freshen them up
• Find a place that will recycle them by giving them to people who need a patio set chairs or table
• Using wood or plywood, bottom part of plastic chair can be covered and turned into dog or cat house
• Cut large hole in a seat area, and a plastic chair can serve as trellis for the plants

Someone else might reuse them if you can't.

• List them on a classified ad or material exchange site.
• Sell them at a yard sale
• Give to friend or relative
• Place them curbside with a 'FREE' sign