  Steadily growing interest in magnetic characterization of organic compounds
for therapeutic purposes or of other irregularly shaped specimens calls for
refinements of experimental methodology to satisfy experimental challenges.
Encapsulation in capsules remains the method of choice, but its applicability
in precise magnetometry is limited. This is particularly true for minute
specimens in the single milligram range as they are outweighed by the capsules
and are subject to large alignment errors. We present here a completely new
experimental methodology that permits 30-fold in situ reduction of the signal
of capsules by substantially restoring the symmetry of the sample holder that
is otherwise broken by the presence of the capsule. In practical terms it means
that the standard 30 mg capsule is seen by the magnetometer as approximately a
1 mg object, effectively opening the window for precise magnetometry of single
milligram specimens. The method is shown to work down to 1.8 K and in the whole
range of the magnetic fields. The method is demonstrated and validated using
the reciprocal space option of MPMS-SQUID magnetometers; however, it can be
easily incorporated in any magnetometer that can accommodate straw sample
holders (i.e., the VSM-SQUID). Importantly, the improved sensitivity is
accomplished relying only on the standard accessories and data reduction method
provided by the SQUID manufacturer, eliminating the need for elaborate raw data
manipulations.
