Even if you do not like anchovies i would ask that you be surprised and at least give this a try.
Olives (from a jar) once opened can last usually for up to 14 days if kept in a refrigerator ,capers (jarred) usually 8 supposedly. I think more on both. They are a great addition to meals and can be an excellent alternative as a stop gap if feeling peckish and dieting.
As for the anchovies blend the olives and capers and olives in a blender or you could probably use the back end of a fork but mash them well. The quantity used in the photo to the right was the quantity used for this recipe as with the lower photo too plus one extra mushroom.