smudge,
the aerosols were one shot and did consist of mainly DDT. It was called disinsection if I recall correctly. We used to carry muti use ones but places like Ozz used to insist on proof that the correct amount (it varied by internal size of the a/c) had been used hence the single dose cans. Upon arrival they were supposed to count the cans and that would be that. But more often than not they would spray us with their own foul mixture. In places like NZ you would then have to paddle through some sheep dip as you got off the a/c.
On 48 at Changi you could sometimes find a Swamp Monitor up the nose or main gear. The SOP was to send for 'Pop' who would remove the creature. No doubt it it had a second life as the star item on the day's curry.