While this has been discussed in the past I reckon this deserves a separate thread.
Shipping crypts isn't difficult (if done correctly) and often the plants will arrive healthy even after travelling for 2 weeks or longer. You may want to trim and rinse the plants (most of this should be done prior to shipping to reduce oxygen consumption as well as rotting of old/damaged tissues) and usually you can go ahead and plant the crypts right away. Avoid burying the rhizome though: leave the rhizome on top of the substrate (in very humid air or, preferably, covered with water); start with a minimal amount of soil and gradually fill the pot later once the plant got established and is actively growing. There are stainless steel "pins" commercially available which can help to anchor new plants but a bent iron nail works just as well.
(No nickel, zinc, lead, or other metals though!)
Plants showing signs of melting usually benefit from letting them float in shallow DI water which has been incubated with peat of good quality for a week or more. I usually use DI water to discourage grow of bacteria/fungi and change it several times during the first week; you'd prefer water from a suitable aquarium for crypts needing really hard water and may want to change that more often (rainwater crypts and even keei do fine with DI water though). I prefer placing each new arrival in a dedicated container rather than letting them float in a tank (too easy to mix things up and also for quarantine purposes); a few grains of granulated peat may help to keep things stable
Sometimes the main growing point rots away and only a piece of rhizome is left. Don't despair - the crypts often come back, even after many months! Rinse the plant thoroughly and use a sharp tool (razor, scalpel, etc. - preferably no scissors) to cut through healthy parts of the rhizome. Place the blade in alcohol (over 90%) and rinse the rhizome again. Examine closely (10x magnifying lens) wether there are still any signs of rotting tissues at the cut or other surfaces; cut again if needed. I also let these float in little containers (label with pencil!). Most will come back soon and develop plantlets from surviving dormant growing points within weeks (up to a few months).
Sometimes the rhizome doesn't show any signs of life for months but still comes back eventually: I find that light helps - light levels could be a little more than regular plants of that species would prefer (if in doubt, use less light though!). If the rhizome turns green (or stays green), that's a very good sign (this is hard or impossible to observe with very dark colored rhizomes though). Basically don't give up as long as the rhizome doesn't get mushy!
In difficult cases, I guess temperature shouldn't be too low either - I head for 25-28°C with plants that need a little pushing...
Once I see the first root or leaf developing I carefully put them on top of soggy or flooded substrate with very little nutrients to get things going. Usually, the plantlets start regrowing from resources stored in the rhizome (even if small) and more nutrients than just a little tease for the developing roots won't do much good and favor grow of algae, etc.