  The idea of exploiting maximally-entangled states as a resource lies at the
core of several modalities of quantum information processing, including secure
quantum communication, quantum computation, and quantum sensing. However, due
to imperfections during or after the entangling gates used to prepare such
states, the amount of entanglement decreases and their quality as a resource
gets degraded. We introduce a low-overhead protocol to reverse this degradation
by partially filtering out a specific type of noise relevant to many quantum
technologies. We present two trapped-ion schemes for the implementation of a
non-unitary probabilistic filter against amplitude damping noise, which can
protect any maximally-entangled pair from spontaneous photon scattering during
or after the two-qubit trapped-ion entangling gates. This filter can be
understood as a protocol for single-copy quasi-distillation, as it uses only
local operations to realise a reversal operation that can be understood in
terms of weak measurements.
