John Who suggests looking for weapons inside of the Thain's museum. (COMIC: The Klepton Parasites [+]TVC comic stories (1964-1965).)
The Thains had a museum in a city on their planet. At least one room of the museum exhibited their weapons, which had not been used in many years. When the Kleptons attacked the city, the First Doctor, John and Gillian encouraged the Thains to acquire heat guns from the museum and use them against the invaders. (COMIC: The Klepton Parasites [+]TVC comic stories (1964-1965).)
