I received an email recently from someone who despaired that the plants she ordered from Thailand were rapidly going downhill soon after arriving, and here is my answer to her question. I thought others could benefit from my thoughts on her problem.
Your question is a good one. Most plants from Thailand will arrive half dead and it is quite a job to revive them. When they rip them out of their media and pack them into a box in 100° temperatures and we get them a week to 10 days later all of those fine thread like roots that you see are essentially dead. They have been dried to a crisp. No amount of soaking will make them alive again. You are basically nearly starting from a cutting when you get these plants.
Here is what I did with a batch of plants I got from AH Hoyas about 6-7 weeks ago, and they all have lived, which is a miracle in itself. I soaked them for a couple of hours, poured the water out of the bucket and left them in there covered with a lid over night. In the morning, I potted them up in a very chunky mix that is damp but not soaking wet. I watered the soil with Dyna-Grow K-L-N Concentrate, which will help build new roots. You have to treat these plants as if they are unrooted cuttings and put them into nearly 100% high humidity conditions for a few weeks until you can see new root growth. I put them into my homemade propagation chambers under grow lights and use net pots so I can see these roots developing. After the roots begin developing, I gradually acclimate them to my conditions.
There are times when the plants you receive are in such terrible shape that nothing can save them, but I think that my method gives them the best chance. I have made videos on my YouTube channel on using net pots and building a propagation chamber. I hope that this information is helpful.