The solid killing agents most often used in killing jars are the cyanides—
1) Potassium cyanide (KCN),
2) Sodium cyanide (NaCN)
3) Calcium cyanide [Ca(CN)2].
*very dangerous, rapid acting poisons with no known antidote*!!
Killing jars or bottles will last longer and give better results if the following simple rules are observed:
(1) Place a few narrow strips of absorbent paper in each jar or bottle to keep it dry and to prevent specimens from mutilating or soiling each other. Replace the strips when they become moist or dirty. This method is useful for most insects except Lepidoptera, which are too difficult to disentangle without damage.
(2) Do not leave killing jars in direct sunlight as they will sweat and rapidly lose their killing power.
(3) If moisture condenses in a jar, wipe it dry with absorbent tissue.
(4) Keep delicate specimens in separate jars so that larger specimens will not damage them.
(5) Do not allow a large number of specimens to accumulate in a jar unless it is to be used specifically for temporary storage.
(6) Do not leave insects in cyanide jars for more than a few hours. The fumes will change the colors of some insects, especially yellows to red, and specimens will generally become brittle and difficult to handle.
(7) If it is necessary to keep insects in killing jars for more than several hours, place the specimens in another container and store them in a refrigerator.
(8) Keep butterflies and moths in jars by themselves so that their hairs and scales will not ruin other kinds of insects.
(9) Never test a killing jar by smelling its contents.
(10) Old jars that no longer kill quickly should be recharged or disposed of by burning or burying.