Which one seems more appropriate?

1. Cache.Clear();
2. Cache.Delete();
3. Cache.Remove();

I would go with Clear unless you either destroy the cache or remove only specified items.

Like clear screen.

Cache.ClearRemoveAndDelete()

Cache.Eradicate()

Seriously tough, I think .Clear() is the better one

Clear()

Cache.Destroy.Clear.Remove.Delete();

Cache.CalculateMonthlyPayment();

Cache.Obliterate()

Clear=remove every item from the cache

Remove=remove one single item

Delete=Delete the cache itself

Cache.Exterminate or Cache.Disintegrate

Cache.Nuke();
Cache.Burgle();

Cache.AndWomen();

@electrineer Cache.With(BlackJack) & Hookers

Cache.Dispose()

Like a proper c# interface implementation

Cache.purge()

On a serious note, what @david-hil said.

Cache.Genocide();

Cache.forget() :3 laravel style

Purge()

Human : Cache.Clear()

Extremist : Cache.Purge()

Micheal Bay : Cache.Explode()

Dalek : Cache.Exterminate()

asdfmovie : Cache.EveryBodyDoTheFlop()

asdfmovie2 : Cache.ILikeTrains()

Hulk : Cache.Smash()

Emoji : Cache.💀()

Internet explorer uses Cache.delete

So anything except that.

I would go with method name Clear

I think Empty() would be the usual term