As for the "borrowers" tendency with Fae work, you can rest assured they really don't pilfer your house clean, and rarely do they take anything we consider valuable.
The kinds of things I notice missing are small - right now, my "oil can" (miniature one) for my spinning wheel is one of their favorite possessions. I cannot figure out why. I just know I ALWAYS put my oil can back on my craft room bookshelves at adult eye level, way too high for my son's 3 year old hands to get into.
And about every 6 months, I will look for my oil can, and lo and behold... it's gone again. When I ask for it back, I find it a few days later somewhere absolutely ridiculous (on top of the piano). They used to adore my Carmex (a lip balm) round little glass containers. They took so many of those over the years. I didn't need them back and never called for them to return those though.
(Alissa's real question... why do Fae need glycerin products???)
Here's the thing I've discovered with Fae energy... they either cannot or simply will not steal. If you tell them you Need the item back, it almost ALWAYS comes back (I'm thinking a 97% return rate) within the next few days to a week. I don't know why this Universal law seems to hold true, but it does - if you notice the item is missing, and you tell them that you Need it back (not want but Need), it will shortly return.
First, you have to notice that the item itself is missing. Often, this is a trick to itself... "Where *is* that red and green plaid bra of mine? My god, I haven't seen it since last year or so? I swear I packed it right here in this drawer, so where is it?" The items they take from my house, sometimes I just don't notice, I think. They're things I don't typically look for every day, or need all the time.
Next, once noticed missing, you call out for it, explain to the empty air why you Need the item for yourself, and it will return. Say it out loud - I know, it's silly, but it has always worked for me. Besides, Fae are great at getting humans to act silly.
You can also set boundaries and Fae are generally not malicious nor wanting to cross those points. ("Look... you guys can have just about anything you want to play with, but you can NOT have this asthmatic inhaler. I know it looks cool, but we Need it, so please respect that.")
Having said all this, I'm ready to be labelled looney...
Your Fae may be far less interactive.
Don't fear them, I say. They are not malicious for the sake of being hateful. They're occassionally cruel to teach you things - example, if you slip and fall, once you're down you have a new perspective, don't you? That's the only kind of "cruelty" I know the Fae will employ.
And they like to make fun of you too - for the purpose of teaching you to laugh at yourself. Fae will drop snow on your head when you sit under trees in winter and then laugh their heads off at the silly human who looks up, like, "What?" They love that kinda stuff.