Turntable cover

If TT has attached cover which swings up, what position should it be in when playing? How does it affect the sound in either position? Or should I remove the cover altogether? If I do, how do I keep the TT free of dust?
TIA for your replies. 
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Test it. Play the same track with it closed, at its default open angle, and removed. Let us know what sounds best.
all TT’s sound best with dust covers removed. Take it off when in listening session and refit it afterwards. Simple as that. My DPS does not even have hinges.
The dust cover is not so easy to take off and on. If I prefer the way it sounds without the cover, I'll probably just leave it off.
I too recommend it off.....use a Swiffer to keep it clean, but be very careful near the cartridge.
One option if it is possible.
Take the cover off, remove the hinges from the back of it and just place it back over the TT when not in use.
That way it still serves its purpose as a dustcover.

This is what I have done on one TT but I do not know what TT you have and if it will just sit on the plinth without hinges.
My old Dual does easily.

Might be worth looking at.
If not and you still would like a usable dustcover when not in use, you could have one made  that would sit on the plinth. Custom made on eBay about $140.
I have a Linn LP12. I'll see what I can do with the hinges.
I have two LP12s. The dust cover will slip right out of the hinges and you can then just pull the hinges out of the holders that are screwed to the back of the wood plinth. No tools needed.

I took some brightly colored rubber tubing and cut four pieces, each about 2” in length. I then slit half way through, the full length of the tube. I then opened up the tubes and slid them over the bottom of the dust cover so the tubes contact the plinth with the dust cover on.

IMHO, the LP12 sounds best with the dust cover completely off, next best with it up and least good with it down. YMMV.
Thanks! I would love to see a photo of your solution.

Email me at viridian(the number 2) at comcast
Keep the cover closed at all times. Make sure you have nice soft felt pads at the points it contacts the base. The cover will actually drop the sound pressure levels around the tonearm and cartridge. As the cartridge tracks the record static electricity is generated which draws dust to the record immediately. I use a grounded sweep arm which discharges the record while it is playing. Sleeve City sells them. They are cheap and very effective. Even if the cover detracts from the sound quality which it definitively does not, keeping your records pristine is more important. The easiest way to clean your  records is do not let them get dirty in the first place.
Seems to me that a dust cover is a large resonating empty box that attracts vibration and delivers it to the table. My Linn cover, when open, just slides out of the hinge slots very easily and the hinges stay put on the lid...I simply stick the lid on a little shelf nearby and back on it goes after a listening session. My old Linn Basik/Akito is utterly immune to audible vibration due to the 3 large cylndrical rubber feet that are loosely attached (or wiggly, per design), and somehow it just keeps on truckin’...great table that hangs on even while I’m often tempted to replace it for no particular reason (the desire for a new and shiny object?).