Not an old wives tale, I remember from school thirty some years ago, Brake fluid (DOT 3 & 4) is Glycol based and hydroscopic or hygroscopic, meaning it is quick to absorb water from it's surroundings. I don't think DOT 5 fluid had been invented yet (It is silicon based and does not absorb water)so they didn't mention it. Anyhoo that's why they don't recommend keeping it around a long time though it should be OK if tightly sealed. Trouble is you can't tell by looking (or smelling) how much moisture it has absorbed over time. Moisture lowers it's boiling point which can = bad news! <img src="/forums/images/graemlins/cheers.gif" alt="" />