I am going to make royal icing with the meriunge powder and I wanted to make spider webs with it (for a spiderman cake)...maybe even some other letters. After I make it, how should I store it? (airtight container? room temperature?)
My party is saturday, and I wanted to make the spiderwebs ahead of time? How far in advance can I make them ? And how should I store them?
Most people store it at room temp in an airtight container with a slightly damp paper towel laid directly on the icing. If mine is colored and ready to go, I like to put a big blob of the icing on a piece of plastic wrap and roll it up (I can't find the link, but there's a forum topic with the method for making these icing "plugs"), and store these frosting packets in a ziploc bag. Then, when I use them, I just snip off one end and drop it in a piping bag. HTH.
You can make the royal icing decorations months in advance if you want, once they're dry just store in a ziploc or airtight container. Room temp is perfect. Think about when you go into the cake decorating store...they have all those royal icing flowers for sale in the glass cases, they've been in there for months.
Don't put a damp towel in with dried decos though, it will "undry" them.
You shouldn't put a damp paper towel in with leftover royal icing if you are storing it - sugar is amazingly hygroscopic and the icing will leach every last drop of moisture out of the paper towel, thus making the icing very thin.
I store leftover royal icing in airtight glass bowls in the fridge. It lasts for months.
I store mine in a tupperware container with some of that Clingwrap that has a sticky side to it, then put the container lid on it. I store my dried royal icing items in tupperware or a glass cake pan, sometimes covered in saran, sometimes not. I cover it mostly to keep out dust than anything else. I also store it out of the light to avoid colours fading.