local element1 = elements.allocate("FLEL", "STFL")
elements.element(elements.FLEL_PT_STFL, elements.element(elements.DEFAULT_PT_BCOL))
elements.property(elements.FLEL_PT_STFL, "Name", "STFL")
elements.property(elements.FLEL_PT_STFL, "Description", "Starter Fluid - Long-burning liquid, good for starting fires.")
elements.property(elements.FLEL_PT_STFL, "Colour", 0xFFC090)
elements.property(elements.FLEL_PT_STFL, "MenuSection", 5)
elements.property(elements.FLEL_PT_STFL, "Gravity", .5)
elements.property(elements.FLEL_PT_STFL, "Flammable", 0)
elements.property(elements.FLEL_PT_STFL, "Explosive", 0)
elements.property(elements.FLEL_PT_STFL, "Loss", 1)
elements.property(elements.FLEL_PT_STFL, "AirLoss", .5)
elements.property(elements.FLEL_PT_STFL, "AirDrag", .01)
elements.property(elements.FLEL_PT_STFL, "Advection", .01)
elements.property(elements.FLEL_PT_STFL, "Weight", 30)
elements.property(elements.FLEL_PT_STFL, "Diffusion", 0)
elements.property(elements.FLEL_PT_STFL, "Falldown", 2)

STFLUpdate = function(i, x, y, s, n)
local clife = tpt.get_property('life', x, y)
if clife > 1 then
for cx = -1, 1, 2 do
for cy = -1, 1, 2 do
tpt.create(x + cx, y + cy, 'plsm')
end
end
tpt.set_property('life', clife - 1, x, y)
elseif clife == 1 then
tpt.set_property('type', 0, x, y)
elseif tpt.get_property('temp', x, y) >= 1273.15 then
tpt.set_property('life', 100, x, y)
elseif s > 0 then
for cx = -1, 1, 2 do
for cy = -1, 1, 2 do
if tpt.get_property('type', x + cx, y + cy) == 4 or tpt.get_property('type', x + cx, y + cy) == 49 then
tpt.set_property('life', 100, x, y)
return true
end
end
end
end
end

tpt.element_func(STFLUpdate, tpt.element('STFL'))

This script creates STFL: Starter Fluid. It can catch fire on contact with FIRE or PLSM, or by being heated past 1000 degrees. Once it catches fire, it will burn for 100 frames, using a method similar to BCOL.

Which 'multiple properties' are you trying to use, and how?

Maybe could you post your code here? I could try to debug it...

Ah, I don't really know much about those. :/