One of the standard protocols for getting rid of bed bugs is to bag all cloth items in the home in plastic bags and take them to the laundomat. Once the bags have been emptied into the machines they should then be discarded as they may have bugs in them. This can be a considerable waste of plastic.
One day when transporting my own work coveralls to the laundromat in plastic bags I grew tired of discarding the bags so I threw the bag into the dryer (on hot) along with my coveralls as an experiment. The bag came out wrinkly but in perfect condition. Since then I have often placed the plastic bags into the dryer and I rarely have a problem. The clear (light blue) recycling bags are more sensitive to heat and they showed signs of heat stress so I stopped using those bags. But the thick black ones were always fine – even in my garage dryer that runs at 190f. My wife has never ruined a bag in our home dryer which runs a little cooler.
I started telling my customers about this finding and one of my customers tried heating the nice thick black plastic garbage bags in the laudromat dryers on hot. Of the 4 dryers she used two loads were fine, one had a heat stressed bag, and one bag was completely melted into a little ball which in turn ruined the clothing. She also noted that some of the clothes appeared to be tinged brown as if they had been burned. I suspect the lint trap was clogged which overheated the machines. The brown tinge might have been actual burning of the material!!
I found that result interesting so I asked for a sample of the bag that melted and placed it into my own garage dryer (190f inputs and a dirty lint trap to slow the air flow and increase temperatures) for half an hour with a single coverall to ensure maximum temperatures. Upon inspection I initially thought the bag was in pristine condition but on careful examination I noticed a small 1.5 inch spot where there was some heat stress.
What we learn here is that some laundromats have their dryers running well in excess of 190f which can melt plastic bags. If you do intend to save your bags by running them through the dryer perhaps choosing “medium” heat would be safer. Or perhaps place all the plastic bags into one dryer and check that dryer frequently to ensure the dryer is not overheating and melting the bags. One might even pull the bags out of the load in mid cycle. Or you might ask the staff if the lint traps have been cleaned recently.
We have found our own home dryer is completely fine for sterilizing thick garbage bags. If you intend to try sterilizing your own bags you should first do some experimentation to ensure nothing untoward happens to the bags. It might be certain brands of garbage bags hold up better than others and different dryers operate at different temperatures and care must be taken. This blog is not a carte blanche endorsement of heating plastic as there are risks involved. Use your brain and take due care. And if you want to be absolutely certain nothing is damaged you can always discard the plastic without heating.
PS
When we move furniture out of an apartment we shrink wrap it in overlapping layers to prevent bed bugs from contaminating public areas. The shrink wrapped furniture is then cooked in my trailer with input temperatures as high as 167f and return temperatures as high as 163f. The shrink wrap has never been damaged. Nor has any plastic bag ever been damaged at those temperatures. That is not to say that it is impossible as there might be some brands of garbage bag that might melt with 160f temperatures but I have yet to see one. The dryer on medium is supposed to be set at 160f. What the actual temperature of that dryer is depends on many factors such as air flow, clogged lint trap, factory settings, or potentially damaged equipment that increases heat beyond factory specification.