Keep them all, do without federal funds. See which the city likes better, money coming in or money going out.
Use the federal funds that would have gone to free school lunches, food stamps, law enforcement grants, etc. in the City/County/State to pay for Federal agents to do all the work themselves instead of expecting assistance from local cops.
And shut down the International Terminal at LAX. If we cannot rely on local assistance to track down visa overstays, obviously no foreign visitors can be allowed to land in sanctuary cities. Same for ships — no non-citizens can disembark.