It can't, because other conductive elements turn into SPRK, a completely different element, with a ctype of the original element. A WWLD signal, on the other hand, is still the same element, just with a ctype. The Clear SPRK function can only clear SPRK; a WWLD signal is not a SPRK, therefore the Clear SPRK function can't clear it.
DMG adds pressure to all avaliable particles nearby and it's adding power to the other
WHOL and BHOL cannot work if covered with gravity tool, the phenomenon becomes more obvious when ctrl is pressed, the tmp of B/WHOL is high and the tool covered them fully.
Shift and Ctrl can change brush shape and effect of tools. The two function have a "conflict". If I use AIR tool when pressing shift, it provides a instant pressure in a line. If shift is relieved before the tool does, the instant linear pressure is still stronger than it would provide without pressing shift.
Forgive my poor English and complicated expression.