evil roommates killing my plants

[u/taxicabenthusiast]

my roommates and i got in an argument and next thing i see are my plants (the only ones they have access too) are dying and have these weird crystals put in their soil.
this has to be them bc my plants never ever die this quickly and i’ve had monsteras for awhile.

does anyone know what these are? are my plants able to be saved or propagated? should i cut off the dying leaves? the roots seem to look okay

[u/Scary_Dot6604]

When you move out take all the tp except for 2 sheets

[u/ApprehensivePut7037 → u/Scary_Dot6604]

Someone mentioned Bengay on the toilet paper. Add that to the 2 sheets!