Hopefully this is not a redicilous idea. I’m pretty new and certainly inexperienced in experimenting much with my own ideas. Basically reading a topic in here on getting rid of unwanted hpuseguests got me thinking creatively. Can’t leave anything under a bed in my case. Can’t even get into the guests room . The idea I fianlly came up with is to write an intention of some symbolism of the intention “get out of my home and out of my life” on their door in some kind invisible magical ink. Of course a type of ‘ink’ one can write in that will vanish as if it was never there at all could have s many magical uses. I am on to anything here or is this honestly just silliness? If anyone has ever do this how did it actually work for you? How did you make and consecrate the invisible ink?
Hey urine makes good invisible ink, when you heat the paper it shows up - I read that in a spy book! 
I’m pretty sure there are ways that could be used.
Lemon juice , milk, vinegar, baking soda (mixed with water and then using cotton swab), or orange juice will have a similar effect.