Containers

Closures and liners

Updated October 2026

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What is here Gasket or membrane Alcohol finds the weak liner Ask with the preservative named The restraint requirement is separate Dome lids for display Standardize, then test one References

For a fluid-preserved collection the liner is the conservation decision.

What is here

222 closures against these necks: 200 continuous thread, 20 dome lids and 2 specialty. By liner, 61 HIS, 38 F217, 30 pressure-sensitive, 25 with no liner, 19 PE foam, 15 foam and 20 of a standard plastisol.

Gasket or membrane

Foam, F217 and plastisol compress against the sealing land and seal only while the cap is on and tight. An induction liner bonds to the land and keeps sealing with the cap off. For long-term fluid storage that difference compounds over years.

Alcohol finds the weak liner

Ethanol is small, mobile and a solvent, so it passes through or attacks several common liner materials. This is the single most common cause of a dried-out specimen, and it is a purchasing decision rather than a storage one.

Ask with the preservative named

Not "is this alcohol resistant" but "has this liner been tested against 70 percent ethanol over years". The first gets an optimistic answer, the second gets a useful one or an honest refusal.

The restraint requirement is separate

If you are ever shipping under 49 CFR 173.4, the closure must be held in place with wire, tape or other positive means regardless of how good the seal is. That is an operation, not a component.

Dome lids for display

20 of them here. They suit a jar meant to be looked at rather than sealed for decades, and they are the wrong choice for anything with fluid in it. Knowing which job the jar has settles this quickly.

Standardize, then test one

One neck finish and one closure across the collection means one compatibility question. Keep a fluid-only control jar sealed the same way and weigh it occasionally, and you will know your own loss rate.

References

49 CFR 173.4, Small quantities for highway and rail. Class 3 and other listed materials are not subject to other requirements where the inner receptacle holds no more than 30 mL of liquid, is not liquid-full at 55 C, is glass, earthenware, metal or plastic of at least 0.2 mm, has any removable closure held securely with wire, tape or other positive means, and is packed with non-reactive absorbent able to take the entire contents inside a strong outer packaging, the whole demonstrated by prototype testing. law.cornell.edu

29 CFR 1910.1200, Hazard Communication, which sets what a shipped container of a hazardous chemical carries and requires a safety data sheet. law.cornell.edu

Written from federal statute and regulation, not from a collection room. Wildlife law is federal, state and sometimes tribal at once, and the Lacey Act makes a state or foreign violation a federal matter. Nothing here is advice on a particular specimen, and the permit questions belong to the Fish and Wildlife Service.