Read: a meta-analysis on smell training

TL;DR: training your nose does seem to work, with caveats.

Read this on the bus: an open-access meta-analysis on olfactory training that pools 36 studies. What it found:
- training improved overall smell function
- the biggest gains were in identifying smells, then in telling them apart, then in picking up faint ones
- longer training went with bigger effects
- the studies varied a lot, and most carried a moderate risk of bias

Basically keep showing up for Priya's threads. That's my two cents.