Solar Heat Grabbers????

[aprilrain1024]

I have read on a couple of posts that people use "heat grabbers". I did a search and didn't come up with anything. The kind I am interested are something like milk jugs painted black(or something to that effect). But what do you do with them? Do you put them in your windows then in the other rooms at night? Sorry if these are stupid questions, but I've never heard of anything like this before. Thanks in advance!
P.s. Sorry if this is in the wrong place, I didn't know where to put it.

[georgiamom]

I read something recently using pennies attached to plywood and you spray them black. You place them in sunlight during the day then bring them in at night and they give off heat at night for sunrooms or places where you want heat. Sprayed milk jugs are also used but someone also recommended anykind of item that you could collect water in sprayed black that could retain sunlight and them release at night.

[sunshine]

There are various types. . .

http://www.motherearthnews.com/Renew...ollectors.aspx

http://www.motherearthnews.com/Do-It...t-Grabber.aspx

http://blog.hemmings.com/index.php/2...a-lot-of-soda/

http://planetgreen.discovery.com/hom...e-furnace.html

http://ecotechdaily.com/2009/07/01/f...ome-soda-cans/

http://www.treehugger.com/files/2007...p_and_easy.php This is the one we use, because it doesn't have to be vented through a window or wall.

[Brat]

I have the black milk jugs filled with water sitting on the floor of the sunroom under the plant stand...they get heated up during the day in the sun and they hold the heat up at night after the sun sets..Keeps the sunroom about the same temp all night that way. I don't fill them all the way full because the expand when they heat up. I also put a teaspoon of bleach in each so they don't grow fungus in them...I also use bleach jugs for this too. It just helps to hold the heat longer after the sun sets..I have a fan in the window that draws the air from that room into the rest of the house and on a sunny winter day heats the whole house most of the day and into the evening..The more you have the more heat they hold.