Cleaning them with brake cleaner is good, it depends though, how many miles are on it?
They play a fairly important role.. venting crank case pressure.(PCV=positive crankcase ventilation) Its probably good practice to replace them every 30-60k miles, preferably with a OEM one, the springs in them will get weak over time and they will not function correctly. If one gets stuck closed, it could lead to oil leaks, if one gets stuck open could cause a vacuum leak and lead to misfires. Just my 2 cents.