Sawyer makes an pen size sprayer that contains 0.5 oz. of Picaridin insect repellent for $3 which works out to $6/oz. You can buy a larger sprayer containing 4 oz. for $6.62 which works out to $1.66/oz. I'm using the 3 oz. bottle because that's what I bought on sale. It only takes a minute to refill the pen sprayer and you save money and keep more plastic out of the landfill.
I feel a little silly making an Instructable for this but I just wanted to let people know how easy it is to refill the pen sprayer. I could see that somebody looking at the sprayer might think you can't remove the sprayer or removing it would damage it because it's on pretty tight.
Step 1: Pry Off the Sprayer
The pen consists of three parts -- the cap, the sprayer and the reservoir. Remove the cap. Take a knife or other thin piece of metal and place it between the sprayer and the reservoir. Twist and the sprayer should separate from the reservoir.
Step 2: Remove the Sprayer
With the sprayer loose, pull the sprayer and attached feed tube out of the reservoir.
Step 3: Refill With Insect Repellent
Pour the insect repellent from the larger 3 oz. bottle (after unscrewing it's sprayer) until the reservoir is almost full but leave a little space for the feed tube and attachment.
If you want to switch insect repellent, put in 100% DEET, 19% DEET, etc. Don't use the lotion but only liquid.
Step 4: Replace Sprayer
Push the sprayer back on until it snaps into place. Put the cap back on and you have 0.5 oz. more to spray.