If you have a reusable clip-on mosquito repeller that's out of refills, don't bother buying refills -- you can make your own just by cutting a slice of orange peel into the same shape as the refill and inserting it into the clip-on.
The key to this trick is to cut just enough peel without getting any of the pith, in the right shape to slide into the clip-on. Extract of orange peels are often used in commercial insect repellants, along with a wealth of other chemicals you may or may not want around your house.
While the orange peel trick is almost certainly not as effective as a commercial refill, the folks at Unplggd have tried it and it works well. What are some of your favourite home insect-repellant remedies? Share your tips in the comments.