are mason jars clean right out of package?

Wondering opinions on this. Are mason jars clean right out of the package. I got a package of 1/2 gallon mason jars with lids already on them for storing flour, grains and other dry goods. do they need to be washed and dried before pouring in flour, cornmeal and such?

Hi Bruce;
I expect that they are very clean.  
But I would wash them anyway. Then you know.

thomas rubino wrote:Hi Bruce;
I expect that they are very clean.  
But I would wash them anyway. Then you know.

My thoughts exactly.   Why take a chance when it's so easy to be sure?

Many years ago (around 1976) I was in a plant that packaged kitchen utensils.  An employee threw up all over the utensils in front of her.  As she ran to the restroom, the floor manager calmly waped off the utensils with a paper towel so she would be able to get right back to work when she returned.

While they look plenty clean, I always notice a weird chemical smell when I open a new one. So I wash them, just in case.

I suspected they're packed with a gas of some kind?  Something that would prevent expansion and contraction during transit and elevation change (think flying on an airplane)?  That's a wild guess, but I notice an odd chemical smell when I first open them.  And when I open new packs of jars, sometimes the lids "explode" off the jar- I unscrew it facing away from me and brace for the lid to launch off the jar and across the room.  I always wash em.  Who knows what was used to sterilize them, even if they don't have a gas in them.  Bleach?  Ammonia?  Alcohol?  What industrial cleaning residue is still on the glass?  

I have both Ball and Kerr jars in my basement, and printed right on the cardboard box they come in they both say to wash them before use.