The amounts reported to you in Box 13 of your K-1, if any, are generally not tax deductible for US individuals. In other words, there is no where for individuals to enter the amounts from Box 13 in order to reduce their income taxable liability on Form 1040. This is because US tax law changes in 2017 no longer allows indivudals to take portfolio deductions against personal income.
Despite the fact that the amounts in Box 13 are not deductible for income tax purposes, investors will need to keep track of the amounts they received in Box 13 each year, in order to properly calculate the taxable gain or loss on their eventual exit of their Masterworks position.
Keep all K-1s for your records as you will need them when your investment ends.