Please be noted that you are able to heat up till 40℃, but you should heat the RM(ISO Tank) as a whole.
In other words, please do not heat some part of RM(ISO Tank), but should heat up gradually.
Just in case, please also take care of Vent while you heat the ISO tank.
FYR, if heating temperature is over 100℃, xylene would be boiled.
Boiling Point is around 135~140℃.