Too Much Magic?

This post is in response to a somewhat common Facebook question, a question I am glad to answer. 

There comes a time in many DnD games (and other RPGs) when the DM (or GM, if you prefer) sits back and thinks, 'well, shit. That thing I gave the party is far more powerful than I anticipated. How do I get it away from them?'

In most cases, the 'thing' involves one or more potent magic items.  One can be an issue, but in large groups - even without clever players - the power magic items grants seems to compound exponentially.  This is even more of an issue in 5e, which is 'balanced' based on PCs having no magic items at all.

The contents of one PC's Portable Hole?

Now, it doesn't matter how the party gained all these items, be it through generous loot or the existence of magic item stores, because the PCs have them now and that is the problem.

Thieves in the night (or capricious Wishes from greedy NPCs) works once or twice, and is overall an unsatisfying way to remove magic items from the game.  This is because it is too often a temporary fix, as PCs will scry the item and pursue the thieves until the item(s) is/are safely where they belong - in the PCs' hands.

So a more permanent solution is necessary.

Earlier rulesets had rules about items needing to make saves if their bearer failed a save, so a barrage of fireballs could generally prune the party of lesser items.  Mordenkainen's Disjunction was another means to permanently destroy a magic item.  Even the lowly Disenchanter and its appetite for magical auras provides a DM with a means to remove bothersome magic items from players.

Disenchanters.  Destroying magic items since 1981.  Artist?, Fiend Folio

The drawback to all these methods of item removal is that they come across as DM fiat or even adversarial DMing.  Nobody wants that in their game, not even the people that think fudging dice in combat 'for narrative reasons' want this.

So what is a poor DM to do?

That poor DM gets the players to dump the items themselves.  This opens up many doors and puts the onus on the players/PCs, rather than on the DM.  

Some examples:

Magic items in hand can be dropped and lost in a PC's haste to escape. Especially in deep water.  Doubly so if the magic item(s) is heavy, like a weapon, shield, or metal armor.

Magic items are the perfect gifts for potent beings, to curry favor or the like.

Magic items are ideal bribes to escape potent angry beings.

Magic items can be suitable trades for other items (a slippery slope) or specific, rare services.

Magic items might be an acceptable ransom for an ally or innocent. 

Magic items sacrificed on pagan altars or to power door locks or to run magitech machines for ... purposes.

Magic items buried with their owners are a fitting end, presuming your game lets PCs die, moreso if your game has a mechanic or reward for a proper Heroic Sendoff (in the middle of the post - an awesome houserule).

AD&D DMG, 1979

My experience is that players gripe far less when the choice is in their hands.

Even if that choice is a bit of a Faustian bargain.  Perhaps especially so.