Plastic bottles are specified as they are made from one of only three polymer types and are very easily identified, both by members of the public and those sorting the collected bottles. The three polymer types used are PET (e.g. fizzy drink bottles and squash bottles), HDPE (e.g. milk bottles and detergent bottles) and PVC (e.g. large squash bottles), although the use of PVC in such applications is in decline.

Items such as margarine tubs and rigid food containers are made from a very wide range of polymer, many of which are blends. These are much more difficult to identify and separate efficiently. It is also more difficult to secure an outlet for the material as mixed plastics are not in high demand.

Yogurt pots are not generally accepted in plastics recycling schemes as they are in fact made from polystyrene. This has an entirely different make-up to the polymers used in bottles and there are currently limited outlets for the material. Again, there are fewer clearly identified end markets for the material at this time. The quality of the material is often compromised as a result of food contamination, making it necessary for householders to thoroughly wash the cartons before depositing for recycling.

In areas where yogurt pots and rigid food containers have been collected, the value of the material has been diminished by a lack of thorough cleaning.

Many people often enquire why they are advised to remove the lids from their plastic bottles when depositing them for recycling. The reason is, again, the lids are made from a different type of plastic to the bottle and, if mixed with the bottles, causes contamination of the polymer type, reducing both the quality and value of the material. This can have implications on the intended end-use of the recycled material due to the contamination's impact on end-product consistency.

Flower pots are another item about which questions are often asked. The majority of flower pots are made from polypropylene, (PP), although some are made from polystyrene. As in the case of rigid food containers and yogurt pots, there are few outlets for collected material and a higher level of contamination.

Carrier bag recycling facilities are now available in some supermarkets. The facilities are not yet widespread due to the very lightweight nature of carrier bags and sale outlets are limited. The material is generally only used for low grade applications such as bin liners because of the contamination effect of the printing ink, making it only suitable for dark colours, such as grey or black.