The only component in HFM to handle Adjustment Values is the Journal Module. We can enter value into the Parent and Child members of the HFM dimension through Submitting and Posting Journals.
If the Journal still exists, unposting journal will remove relevant values from Adjustment Value dimension members.
If the Journal has been deleted, but posted values are still in the application you can create an Offset Journal and post it to the Same Point of View (POV), where the accidental value is present. An Offset Journal is a Journal posted to the POV with the opposite value as the one already existing in the cell to make the value in the cell equal zero.