I have tried turning the key backwards, pressing a button, turning off the skidsteer and it never seems to help. Most of the time the pressure is in the hoses of the attachment and not on the skid steer. The best solution I have found is to unhook your attachment hoses after running the machine when they are hot. Otherwise, crack open a fitting to release a little oil.
Newer bobcat skid steers have different connectors that allow the pressure from each attachment hose to be released before disconnecting. Each coupler is depressed before unhooking hoses. These work much better than the standard couplers found on most skid steers.