Strict attention to hygiene and use of disinfectants, both...
No matter where you go on earth, if humans are present, you'll be able to find trash. One of the most common forms of trash is plastic bottles, whether they're from water, soda, juice, cooking oil, or cleaning products. Environmentalists tell us that some of these bottles may be around for hundreds of years without biodegrading—while that's not a good thing from an environmental standpoint, it's of great importance to survivalists.
So, since we know that plastic bottles are easy to find (and will likely remain that way for centuries), how can we re-purpose them into a survival resource? Well, you could combine it with a flashlight to create a water bottle lantern, or you could break it down into another valuable item: cordage.
The video below from North Carolina Prepper shows how to build a jig, or a device that holds your work in place as you dissect the bottle. This jig uses nothing more than a piece of wood, two bolts and nuts, a few washers, and a razor blade to slice the bottle in to thin strips.
These plastic strips could be cut thick for weaving into baskets and fish traps, or they could be cut thin to serve as simple cordage. Of course, the thicker these strips are cut, the more they're going to want to retain their cylindrical shape, so keep that in mind.
North Carolina Prepper also theorizes in the video that aluminum cans could be broken down in a similar manner, and we could definitely see many potential uses for thin aluminum strips. The metal strips could be used any way flexible wire would be, including being twisted and braided to form strong cords.
As they say, one man's trash is another man's treasure, so this technique to make cordage from bottles or cans is beneficial for survival.