Boveda Case Seasoning 72% RH 2-Way Humidity Control Replacement for Use in Fabric Holder. Size 60 . Most wood instrument cases have twice as much wood as your instrument does! All of that wood needs to be humidified before using your Boveda Starter Kit (sold separately). If you don't season your wooden case, you'll blow through Boveda faster than you need to—so start off by seasoning that case in one-step with Boveda for seasoning. Wooden instrument case? If you place a perfectly humidified instrument into a dry case, the case will draw moisture out of your instrument. Prepare a wooden instrument case, called “case seasoning,” before using Boveda 49% RH to control humidity for a fretted or bowed wooden instrument Seasons an instrument case in one step. Place all 4 Boveda 72% RH in your wooden instrument case, close the lid and keep it closed for 7 to 10 days. Moisture from Boveda automatically absorbs into the wood of your case. After 7 to 10 days, remove Boveda for seasoning from your case and discard them. Case seasoning is not required if your case is made of synthetic material or if you use a wooden instrument case in high-humidity climate. Unopened, Boveda can stay fresh for up to 2 years in its overwrap and sealed bags.