There are 2 "standard" tools used by microscopists to manipulate tiny
objects. One is an insect pin mounted on a suitable handle. Insect pins come
in assorted thicknesses. The finest ones are known as "minutens" from the
German name. They are available from entomology supply houses. One such place
is BioQuip Products ([log in to unmask]). The other tool is a cat's whisker,
again mounted on a handle. They are available at the places where cats
routinely sleep (don't pull them off a cat's face; it will hurt the cat &
besides, the cat needs them). A whisker starts out thick & gradually gets
finer. It can be cut at a suitable place to obtain a probe of desired
thickness.
 
Be careful, however, when manipulating tiny shells with a needle or a
whisker, because one fling from a needle could send your shell flying across
the room.
 
Micro shells may be mounted on non-drying modeling clay on a microscope
slide. This was recommended in an old article on Vertigo by McMillan in the
Annals of Carnegie Museum.
 
A.