Blowing before the swab was new to me...
Coulda,Shoulda,Woulda? Many things have been disproven, proven, disproven...
I was watching the live White House press conference when Dr Fauci said 'Don't wear a mask' in March 2020.
Anyway, I have never waited to be led by the nose :-)
Here is a link to another nostrils intervention substance:
https://pubmed.ncbi.nlm.nih.gov/33759682/
(No problems with wiping out nostrils with mouthwash so far... and the good news is I found my recalled advanced whitening toothpaste on Amazon.)
They have always recommended blowing your nose before testing.
From 2020:
https://www.mass.gov/doc/what-if-i-need-to-be-tested-for-covid-19/download
https://dpbh.nv.gov/uploadedFiles/dpbh.nv.gov/content/Reg/EMS/dta/Training/Covid%20Power%20Point.pdf
https://theconversation.com/goodbye-brain-scrapers-covid-19-tests-now-use-gentler-nose-swabs-144416
https://www.cpllabs.com/covid-19/covid-19-nasal-swab-collection/
Haven't we already covered that mouthwash in your nostrils hasn't been proven to do anything, and may be harmful? We are an evidence based site. There is no evidence that this does anything.