I tried that, but couldn't find any that didn't have auto-shut-off because of laws here. (people leaving 'em on all night and frying granny is bad i guess)
Top of an old CRT computer monitor not allowed to go to sleep gets to about 85-100F.
I just use some old Jiffy tray holders as spacers so it stays about 85-ish and aluminum foil in case of drips....water going in the top of a CRT is
BAD.
Like so:
old cinnamon roll tray w/ Pro-Mix BX, and a $2 thermeter on top of a $6 CRT. A dbl'd-up styro cup in background w/ clingwrap.
The old Jiffy tray being used to diffuse some of the heat and allow the CRT to still do so as well.
Lots of those old CRT's can be found for free, why not use 'em?