I got my visa for 2008-2011, but never travelled on that.
If now I plan to visit what needs to be done to use the H1B cap.
Approval was 2008-2011
Got H1 stamped in 2010
Never travelled to US.
Planning to reuse H1B cap
IMO, your H-1 cap-exempt period expired in 2014 (6 years from original H-1B approval date).
However, there are others who have said 6 year period starts from original H-1B expiration date. Using that, you have until 2017 to file a cap-exempt petition.
Still, there are others who have mentioned that it can be done even after 6 years: H1B "Remainder" Approvals, Even After Long Absence from U.S. - Murthy Law Firm | U.S Immigration Law