One way to save funding is to return unobligated funds to the Treasury or require agencies to use the funding for legitimate purposes.
Another way to save funding is for lawmakers to enact a law to streamline the contract closeout process to deobligate uncosted balances (aka carryover) from old contracts. Because DCAA audits and final invoice may be needed before a contract is closed out and funds deobligated, the deobligation of uncosted balances for T&M, Labor Hour contracts, and cost type contracts can take up to 6 years. The DCAA is also apparently backlogged with other priorities for DOD. Some contracts/grants period of performance have long passed but it takes years to close them. Deobligated funds can also be used for legitimate purposes by agencies.