Prior to going into OCLC, save as a .txt file the OCLC numbers of bibliographic records whose holdings you wish to delete. One number per line. No prefixes, numbers only.

Open OCLC

When doing this for the first time, check that the Batch deletion settings are good. 

Under Batch, click on Holdings by OCLC Number

Use Browse button to navigate to your saved text file of OCLC numbers for deletion of holdings

Location of the file should show in the Import File of OCLC Numbers window

Hit Import Button

Window asking do you want to delete original import file--No

In Action box, select Delete Holdings. 

Hit Okay 

A report will appear after the file is processed. It should show all deletions with totals at the top.

Check the first and last OCLC number in the report against your first and last number in the file. You can print this report, but not save it. 

If the report contains errors, correct these by hand.