Well, one thing that I am always careful of when bringing in something that 
I've "stored" in my shed or garage for a while, *especially* in colder 
weather (as we are heading into here in New England, and as you would be down 
ther in MD), is to give them a full day inside the house to acclimate to the 
warm temperature before ever applying power and spinning them up.  If you 
spin up a cold drive they tend to warm up rather quickly, and the rapid 
temperature change can do strange things to the oxide of the platter, the 
expansion of the platter, etc...   I actually prefer to wait longer than 24 
hrs if possible.  Even after just a few hours, the outside of the drive may 
be room temperature, but the temp inside the drive may not have gotten up to 
a decent temperature yet.   And those 5-1/4" drives have a lot more mass in 
them to warm up than these little 3-1/2's these days.

What is happening to them?   Do they spin up at all?  I remember the old 
Quantum drives in the early 68K Macs (20's, 40's, & 80's) tended to seize up 
if the drive was spun down for a while.  The grease in the bearings would get 
tough, and the drive motor couldn't get it started.  If you powered the 
machine off and on several times, giving the bearing that initial "shock" 
from the motor starting, eventually the bearing would get moving and the 
drive would run fine...  until you powered it down the next time for an hour 
or so.  We started telling the people who had this happen to leave their 
machines on 24/7 so the drive would keep spinning...  and, of course, to back 
up anything important in case we had to (eventually) swap the drive.

If they are spinning up, do they "clunk" and spin down?  Sure sign of a 
crash... in which case just trash it.  

Pete