This is the shortened form of the full idiom, 'better the devil you know than one you do not’, and means that it is often better to deal with someone or something you are familiar with and know, even if they are not ideal, than take a risk with an unknown person or thing. And this precisely is the topic EarthyyBags, the ever vigilant protector of the earth harps on when dealing with plastic.
One of the most essential issues in dealing with plastics for both health and environmental purposes relates to getting familiar with different grades of plastic that range from 1 to 7, while the following paragraphs will help you know them better.
Plastic Grade: 1 is identified as Polyethylene terephthalate, which is also known as PETE or PET. Normally clear in color, the vast majority of disposable beverage and food containers and bottles are made of this. Another common set you’d find this grade of plastic is in your household cleaning product containers. This plastic is relatively safe, but it is important to keep it out of the heat or it could cause carcinogens (like the flame retardant antimony trioxide) to leach into your liquids. Plus, the porous nature of its surface allows bacteria and flavor to accumulate, so avoid reusing these bottles as makeshift containers. This plastic is picked up by most curbside recycling programs.
Plastic Grade: 2 is identified as High-density polyethylene, or HDPE. Most milk jugs, detergent and juice bottles, butter tubs, and toiletries containers are made of this. Usually opaque in color, this plastic is considered safe and has low risk of leaching. It is picked up by most recycling programs.
Plastic Grade: 3 is identified as Polyvinyl chloride, or PVC. It is used to make food wrap, bottles for cooking oil, shower curtains, inflatable mattresses, and household plumbing pipes. PVC, although tough in terms of strength, it is not considered safe for cooking or heating. It contains softening chemicals called phthalates that interfere with hormonal development. Never cook using food wrap, especially in a microwave oven. Check the labels of inflatable, baby toys, etc. to ensure they are free of PVC (and phthalates and BPA). This plastic is seldom considered during recycling programs.
Plastic Grade: 4 is identified as Low-density polyethylene (LDPE) and is used to make grocery bags, food wraps, squeezable bottles, and bread bags. This grade of plastic is also considered to be relatively safe. The problem with LDPE is mainly an environmental one: It is not recyclable via curbside and other recycling programs. They may be reused as grocery or doggie bags rather than being thrown away after one use. Of course, one would ideally have reusable totes for groceries use biodegradable poop bags.
Plastic Grade: 5 is identified as Polypropylene (PP). Common items produced with it include yogurt cups, medicine and ketchup bottles, kitchenware and “microwave-safe” plastic containers. Polypropylene is considered microwave-safe because it is heat resistant and therefore won’t get warped in the microwave. This does not mean it is healthy for you to consume foods which have been microwaved in it! It is always best to microwave in glass containers (there are variations in microwavable glass types as well). As long as you avoid the microwave, PP is considered a safe plastic.
Plastic Grade: 6 is identified as Polystyrene, or Styrofoam, from which most disposable containers are made. However, evidence suggests that this type of plastic leaches potentially toxic chemicals, especially when heated. It would be wise to avoid #6 plastic as much as possible. It is difficult to recycle and only accepted by specific recycling facilities. Even worse, when not recycled, it takes ages to decompose.
Plastic Grade: 7 primarily suggests as ‘everything else’ while being composed of substances such as bioplastics as well as anything else. This is one of the reasons why the use of plastic of this grade may be considered to be ‘at your own risk’ as you are completely in the dark as to what comprises it, that include highly toxic BPA. Items produced with this grade of plastic include water bottles, sports equipment, medical and dental devices, CD's and DVD's, and some computer and other technological parts. It is wise to dispose of any food or drink related product that is known to contain BPA. It is difficult to recycle #7 plastic and most curbside recycling programs won't accept it.
To be honest about it, you need to stay away from plastics, but that can be difficult in such a plastic heavy society. If, however, you are going to use them, you need to remember which are less hazardous. To summarize, plastics in categories #2, #4 and #5 are generally considered safe. Nevertheless, be wary of putting them in the microwave, even if they are labeled “microwave-safe”. Plastics #1, #3, #6 and #7 should be used with varying to extreme caution, especially around food or drink. Of these, plastic #1 isn’t too terrible, but needs to be stored in cool environments and should not be reused.