More recently: a 2017 mask decontamination study from Taiwan that compared a number of commonly-available solutions, using several mask types including N95:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5638397/

Surprisingly, the method that worked best was...

> "Place the test masks in a traditional electric rice cooker using dry heat for 3 minutes (149~164°C, without adding water)."

Apparently dry heat was much better at preserving the structural integrity of the different masks, compared to chemicals or steam.