Pour the GBL solution into a centrifuge tube and set the centrifuge speed (5000-8000 rpm, 5-10 minutes). After centrifugation, the cellulose precipitate will be concentrated at the bottom of the centrifuge tube. Pour out the clear GBL solution on the top layer without stirring the precipitate. If there is any small residual cellulose, centrifuge it multiple times.
I know that Switzer's reagent can dissolve cellulose, I can't remember what all it is, like h2so4, ammonium hydroxide, copper sulfate, some of those and more...I just learned about it recently
you can just run the synth with Naoh and the cellulose wil form a bal like structure and just squuze the ghb out
if ya also have the blue colour problem tthen make a big cobon filert out of pvc pipe and fill ot with 2 boxes of aquarium activated carbon run it trough the carbon filter for an hour or 4 and you have clear ghb