Add the warm water slowly, mixing all the while so it won't be too lumpy. A whisk works well for this.
Store in a jar.
When ready to use, put cotton into the top of a jar lid to fill it, and then saturate the cotton to the top.
Place where you want it; make several if you need it.
This will keep for a long while.
Drip a drop or two over the edge of the lid to rest on the counter so they will find it sooner.
It sometimes takes a little while for them to find it, but find it they will.
When they do, let them alone; you will want to kill them because they look so creepy; but don't because they will hang over the edge of the lid and drink, drink, drink, and then take it back to the nest.
Almost over night, they will be gone.