Drying peppers for a spice shaker?

of plastic in a layer 1 or 2 deep with plenty of gaps between them for airflow, and leave them out on the living room floor out of the way for a few (maybe 2 or slightly more) months during the winter.  As long as you're in a climate where you get dry air naturally or from running your furnace they'll dry just fine.  Cayennes have extremely thin flesh though.  Thicker meat peppers you will likely need a dehydrator for if you don't heat your house with something like a wood burner.  They may dry but they may develop black or white molds on the inside too.   Habaneros and Scorpions are fairly thin, but to me they always seemed to be more susceptible than cayennes to mold or rot just sitting out in the open.

Make sure they are thoroughly dry before processing and jarring them or they can mold.

And as VR below said - When they crush to flakes between fingers they're done.

they are dry enough

for quite a few years. I make a Thai chili seasoning and a ghost pepper seasoning.  Be very careful with mixtures.  I use the Scorpion peppers for a hot sauce mix. We cook regularly with the thai seasoning and I use the Ghost Pepper seasoning to strictly make Ghost Pepper Andouillie.  The hot sauce is made to use one drop in a bowl of gumbo.  Any more and it gets kind of unbearable.

Thai Chilis are 150,000 scoville units, Ghost Peppers are 1.5 million and the scorpions come in at 2 million.

I don't know.  I guess it depends where your located and how warm it is there.  I would  use the oven on really low heat to help edge them along.  I think you'll be able to tell by the feel.  Just don't rub your eyes afterward!!!!  Yikes!