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I take it that you depressed one of the check valves and you got a spray of Freon. In that case, it says that your system is sealed well and may be operational. It all depends on how much [static] pressure is in the system. With any system pressure, there should be no problem with turning it on; you can be certain that there is adequate lubricating oil and that there is no moisture in the system. Try it out....see what happens. The most you might need is a bit of a recharge.
if there is pressure after 5 years then it is at worst a slow leak and you can probably get by with a recharge to top it off that will last a couple of years... alot cheaper than the labor to evacuate, find and fix any small leak, plus parts, and recharge , with oil charge, totally from empty...
those evacuators that suck up and store the freon ( whatever R-xx it is) are not cheap and shops charge alot to use it...
of course you can't legally dump freon into the atmosphere ( save the ozone layer so you don't get skin cancer ) so if you do have a leak you are obligated to spend the big bucks to fix it....