Hope this doesn't turn in to a "LOTION / NO LOTION" debate like the one about the magnets in another thread on this forum!!! Some things never change, reminds me of the Goop/No Goop bebates of years gone by.
The first time i saw it used was by the 1/10 on road RC people on there UFRA [or what is now known by slotters as fish rubber] tyres in the early 90's, then there was bebate about what make and what factor was best! I use it mainly to freshen the tyres if they haven't been used for a while and sometimes before my heats at a race, depends on the track conditions at the time. It can also be used on certain rubber tyres, works well on Fly and the Airfix/Mrrc tyres.