Lt.-Col. (res.) Idan Sharon Ketler, Deputy Commander of the IDF's Loot Removal Unit, gave an interview to Reshet Bet Radio program "Rina and Akiva" to discuss what the IDF has found in Gaza and how it handles it.
According to Ketler, "loot" is defined as anything that is used for warfare or which serves to aid terrorist groups. Whenever IDF soldiers operating in Gaza find money or property which seems to fit the definition, they either call in the unit to pick it up or take it with them to hand over to the unit at a rendezvous point.
Ketler says that tens of millions worth of Hamas funds have been seized from the Strip. The overwhelming majority of it is in shekels, though a lot of it is in dollars. The money has been found in safes, closets, tunnels, and even inside mattresses.
Once the Loot Removal Unit has the money, it is then carefully counted and catalogued under close supervision. The unit used to count by hand but was soon overwhelmed, so it brought in bill and coin counting machines from local banks.
Once that process is over, the money and assets are handed over to the kupah rashit or main account unit in the Defense Ministry, where it is officially confiscated and allocated to the country's budget.
Not all valuables can be seized - only those related to combat and terror purposes. Things like diamonds which may simply be private property cannot be seized without careful deliberation, to say nothing of the international laws regulating diamonds.