You can also coat the pieces with a wax emulsion sometimes called "Anchorseal". Wood working stores carry it.
The wax emulsion slows down the drying process.
I would coat with the wax emulsion, and put in a paper bag, and store in a cool place. Then I would check occasionally and fill any cracks with super glue.
If you go to the AAW forums and do a search on drying wood you will get all kinds of recomendations.
Some boil the wood, others freeze it, others microwave it, some soak it in dishwater soap, others soak in DNA.
I don't think there is any sure way to speed up the drying process without the risk of warps and cracks.