I also asked Google, and got a complex answer which WORKS.
It takes a minute for the batchfile to execute,
but if I click its shortcut, the effect is instantaneous.
Firefox must NOT be open when the batch is run !
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
REM - substituting 'v7pvfr41.default-release' for '*' renders it ineffective,
REM - even though that is the folder where those 3 sqlite files are held
for /d %%x in (C:\Users\Joe\AppData\Roaming\Mozilla\Firefox\Profiles\*) do (
del /q /s /f "%%x\places.sqlite"
del /q /s /f "%%x\places.sqlite-shm"
del /q /s /f "%%x\places.sqlite-wal"
)
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
I would love to know what 'for /d %%x in' does or means
and why it is rendered ineffective when '*' is substituted for.