  High resolution and sensitivity large-scale radio surveys of the Milky Way
are critical in the discovery of very low surface brightness supernova remnants
(SNRs), which may constitute a significant portion of the Galactic SNRs still
unaccounted for (ostensibly the Missing SNR problem). The overall purpose here
is to present the results of a systematic, deep data-mining of the Canadian
Galactic Plane Survey (CGPS) for faint, extended non-thermal and polarized
emission structures that are likely the shells of uncatalogued supernova
remnants. We examine 5$\times$5 degree mosaics from the entire 1420 MHz
continuum and polarization dataset of the CGPS after removing unresolved point
sources and subsequently smoothing them. Newly revealed extended emission
objects are compared to similarly-prepared CGPS 408 MHz continuum mosaics, as
well as to source-removed mosaics from various existing radio surveys at 4.8
GHz, 2.7 GHz, and 327 MHz, to identify candidates with non-thermal emission
characteristics. We integrate flux densities at each frequency to characterise
the radio spectra behaviour of these candidates. We further look for mid- and
high-frequency (1420 MHz, 4.8 GHz) ordered polarized emission from the limb
brightened shell-like continuum features that the candidates sport. Finally, we
use IR and optical maps to provide additional backing evidence. Here we present
evidence that five new objects, identified as filling all or some of the
criteria above, are strong candidates for new SNRs. These five are designated
by their Galactic coordinate names G108.5+11.0, G128.5+2.6, G149.5+3.2,
G150.8+3.8, and G160.1$-$1.1. These discoveries represent a significant
increase in the number of SNRs known in the outer Galaxy second quadrant of
longitude (90$^{\circ} \leq \ell \leq $180$^{\circ}$).
