THE FOG ON THE LINE

I did some fire prevention training at home today - all part of lockdown employment - and there were some invisible sections that needed illuminating.

It so reminded me of something from childhood and all I could think of was invisible writing but I'm just foggy about what it actually was.

For some reason I have those Witch pens in my head. Were they for invisible writing? Were there other invisible writing pens?

Can anyone de-fog this?

invisible ink in the sixties: we didn't see that coming

Did you use invisible ink when you were a Sixties or Seventies nipper?

I know I did. I used to love writing secret messages and revealing them somehow.

Not sure at all anymore how I revealed my messages though! Did you have to wait till it dried?

I seem to remember a particular toy that included invisible ink. There wasn't any in my favourite spy case Secret Sam though I don't think.

Could it have been those Witch shaped thick felt pens? They had plastic witches pointed hats on them.

Did you use invisible ink? Could it be manufactured at home?