brake clean most likely, hell at the price i'd just replace it shouldnt be very expensive at all. also take a look at all of the components of the system including condition of the hoses and what not, look for cracks / hardness / tears. if any of the above replace. blow some air through it, attach an air nozzle with it set to some low pressure like 10psi probably even a little less and blow air through it to clear any crap out of it,
next check to make sure it only lets air go 1 way, should be a one way valve if i recall, if not replace. shake it, does it rattle? if not replace. most of these will fix a pcv system problem so just take the time and look into that. otherwise check the side of the engine and look for some stains, look at the condition of the coolant, is there any weirdness to it, such as a mixture or change in color. if its brown, your system might be rusting lol or you just have really old coolant in the system. hows your oil? milky at all, do an oil change. take a good look at it. compression test it, see if you get at least i think the spec was 125-118 psi? i forget, just check all across the board and make sure you dont have a 15%-20% difference, if you say get 120psi on cylinders 1,2,3,5,6 but 4 is 90psi i'd start asking questions, but this still doesnt label it as a BHG it could be somthing else "piston rings, valves not seating, blah blah blah" but other problems have other symptoms. if the BHG is bad enough like mine was it will basically kill the spark lol and you will hear the difference in your exhaust system it putts
tell us all of your symptoms, do the tests, then get back to us and we will tell you if its bad news or good news
