Hello junebug,

Consider removing and saving as much of the substrate as possible. ( if you are going to put the same frogs back into the enclosure)
Put into a storage container w a non-air tight lid.
Tip it up several inches so any left over moisture drains.
I have even used a big plastic spaghetti strainer over a bucket to let soil drain (into the bucket)
You'll be crazed trying to remove the isopods.
Removing the springs is just about impossible.
Substrate/ soil can be re-used as long as it does not smell ( ie has been draining properly)
Give it the whiff test !

I would supplement the soil, however before re-using it:
1) Josh's ABG ABG, Atlanta Botanical Gardens Mix | Reptile Substrate | Josh's Frogs
2)2-3 Josh's springs - charcoal and all ! Temperate Springtail (Colombella) Culture (32 oz) - Springtails | Josh's Frogs
( I would add these now -including the charcoal - rather than later- adding the springs to the storage bin will start to help clean things up)
3) feed the springs and the isopods now to keep the colonies going.

I use green summer zucchini the isopods
If you are pulling out any old wood your are not going to re-use; throw that in the bin as well for the pods.
For the springs I feed "Solgar " brewers yeast ( powder) and Josh's springtail food.

Josh's Frogs Spring to Life Springtail Food (5 oz) - Springtails | Josh's Frogs
Solgar, Brewer's Yeast Powder, 14 oz (400 g) - iHerb.com

One or both of these foods can be put into the storage bin; lightly dusting it on top / very gently mix into the very top layer of the soil. Keep in mine , you don't want any frogs walking over the springtail foods.

Having new/extra ABG on hand can also be use to temporally re-pot any plants that are going back into the enclosure or keep plants moving forward for additional builds.

note:
If your are getting new frogs for this re-build ...... then I would discard ALL of the soil
and completely disinfect the enclosure and any deco that might be going back in or stored.
Now this is a matter of opinion and needs to be your decision.
Some people just set used substrate aside/ store it - for months and months.

Have fun with your new build.