How to delete an attachment in Clearquest using OSLC
Accepted answer
I would suggest to ask in a ClearQuest forum or in a general OSLC forum, if this is possible.
I am pretty sure that it is not supported for EWM/RTC and I doubt if it is implemented in ClearQuest.
Usually you would remove the attribute content that you want to get rid of and PUT that. It is however unclear if that is supported and also if that really deletes the attachment even if it does not show up any more.