The patch tests described in Storm Crows post clearly indicates the fact that only a small amount of THC metabolites are excreted through the sweat....

We evaluated Δ9-tetrahydrocannabinol (THC) excretion in 11 daily cannabis users after cessation of drug use. PharmChek® sweat patches worn for 7 days were analyzed for THC by gas chromatographyâ??mass spectrometry (GC/MS). The limit of quantification (LOQ) for the method was 0.4 ng THC/patch. Sweat patches worn the first week of continuously monitored abstinence had THC above the United States Substance Abuse Mental Health Services Administration's proposed cutoff concentration for federal workplace testing of 1 ng THC/patch. Mean ± S.E.M. THC concentrations were 3.85 ± 0.86 ng THC/patch.
Mean ± S.E.M. THC concentrations of 3.85 ± 0.86 ng is only a small amount.

Quote Originally Posted by Stigma420247
if sweating does not release a substantial amount of thc how is it being detected 1 - 4 weeks AFTER smoking has stopped???
The answer to that is simple: The devices used for detection (sweat patch) utilize a low cutoff range....as evidenced in Storm Crows post....

The limit of quantification (LOQ) for the method was 0.4 ng THC/patch. Sweat patches worn the first week of continuously monitored abstinence had THC above the United States Substance Abuse Mental Health Services Administration's proposed cutoff concentration for federal workplace testing of 1 ng THC/patch.
Sweat patch tests utilize a low cutoff limit for the reason that only a small amount of THC is excreted through sweat.