Blanch the limes in boiling water for 60 seconds. No more than 70 seconds, becuase you don't want to actually cook the limes in the hot water.
Add the limes to your prepared ice bath.
After at least 2 minutes in the ice bath, dry the limes using a dish towel.
Space out the limes directly on the rack of your oven or dehydrator.
Dry until dark brown and hollow, which takes up to 4 days in the dehydrator and up to 3 weeks in the right outside environment. See notes for more details.
Store in an airtight container at room temperature for many months. If not fully dehydrated, they will not last as long.
Notes
* You can use as many limes as you want, as long as you can properly space them on the dehydrator or oven racks. The more you use, the longer it may take because there is more that needs to be dehydrated.Do not leave the oven on when you are not around. I leave it on when I am sleeping, but don't recommend that for safety reasons. Use your own judgment.Placing the limes directly on the oven rack helps them dry evenly. You can even rotate them to encourage even drying.You can dry the limes in the sun if you live in a warm, arid environment. They will not dry properly in a humid environment. Simply place them in the sun for 2+ weeks until completely dry and hard. Feel free to do a combination of sun-drying and oven/dehydrator drying. You can use residual heat after using the oven, or place them near a heat source in your house to reduce oven/dehydrator time, too.