Can I deduct clean up costs ordered by city on vacant land owned by me (AZ) in another state (CA)

Do you hold the land as an investment and collect rent? Is it used for a business purpose? If so, these costs may be deductible. If the land is held for personal purposes only, the cleanup costs are not deductible.

For investment land, you can deduct maintenance costs against investment income.  If you don't have income (because you are holding it to sell later) you can capitalize the maintenance costs. This means that you add the maintenance costs to your cost basis instead of deducting them in the year you pay them.  This reduces your capital gains when you sell.  To capitalize the costs, you have to attach a written statement to your tax return for each year you have costs to capitalize, and you can't e-file.

If this is personal property, maintenance is not tax deductible.