Can vaseline be used to ensure a negative on covid-19 pcr tests?

As a canadian I came across this group of people

>https://www.narcity.com/phac-says-using-vaseline-to-distort-covid-19-test-results-could-actually-be-hazardous

who used vaseline to ensure a negative on their pcr. now idk if it was a joke made by them or not, but canada health agencies are doing absolute damage control so now i wonder, does using vaseline ensure a negative on a pcr?

or is it true that u will get "inconclusive"?

this is very useful for travellers, being able to ensure negative pcrs is very helpful for travelling across borders....