I have seen on a few occasions where damselflies cleaning its eyes with their forelegs. Surely this must be to restore good vision by removing dirt etc.
On other times, they would curve their abdomen downwards using their hindlegs to clean the appendages at the end of the abdomen as shown below. Cleaning the appendages must be important because the male is dependant on them to grab the females pronotum, when he is reproducing, i.e. mating.
If you have other thoughts on why their perform the above acts, please share with me.