It’s possible to reuse rosin press bags. They can be cleaned with alcohol and water, the aim is to remove as much as debris from rosin bags.
But please be aware the seams of the rosin press bags will stretch once used which in turn have a drastic effect on the pressure level during each extraction process. You may also find the extraction is not pure as the previous press.
Hence, ideally it is better to use a brand new rosin bag for each rosin pressing session. This can avoid blowouts and increase yield & quality.