A method for controlling the use of oligonucleotide sequences released from arrays, comprises synthesizing a chemical array of oligonucleotides on a substrate under conditions for producing an array of cleavable oligonucleotides that are blocked from enzymatic reactions after cleavage. Methods may also include receiving a chemical array of cleavable oligonucleotides on a substrate, and cleaving the oligonucleotides from the array, wherein the oligonucleotides are blocked from enzymatic reactions after cleavage. Arrays, populations of oligonucleotides and kits are also provided to facilitate the methods.