  AGBs and YSOs often share the same domains in IR color-magnitude or
color-color diagrams leading to potential mis-classification. We extracted a
list of AGB interlopers from the published YSO catalogues using the periodogram
analysis on NEOWISE time series data. YSO IR variability is typically
stochastic and linked to episodic mass accretion. Furthermore, most variable
YSOs are at an early evolutionary stage, with significant surrounding envelope
and/or disk material. In contrast, AGBs are often identified by a well defined
sinusoidal variability with periods of a few hundreds days. From our
periodogram analysis of all known low mass YSOs in the Gould Belt, we find 85
AGB candidates, out of which 62 were previously classified as late-stage Class
III YSOs. Most of these new AGB candidates have similar IR colors to O-rich
AGBs. We observed 73 of these AGB candidates in the H2O, CH3OH and SiO maser
lines to further reveal their nature. The SiO maser emission was detected in 10
sources, confirming them as AGBs since low mass YSOs, especially Class III
YSOs, do not show such maser emission. The H2O and CH3OH maser lines were
detected in none of our targets.
