What is the ruling on purifying clothes licked by a dog, by washing them seven times with detergent in an automatic washing machine, and is dust necessary? And what is the method for purifying a hair straightener? And do the water and the vessel used in washing with dust become impure?

It is advisable to disregard obsessive thoughts due to the harm they cause. A dog opening a bag with its mouth does not render everything inside it impure; rather, only what is certain to have been touched by the dog's saliva becomes impure, while everything else remains pure in principle. What is confirmed to be impure should be purified by washing the contaminated spot seven times, one of them with earth (or something that serves its purpose, like soap). The water or the vessel is not deemed impure after the trace of saliva has been removed. It is not obligatory to purify all items, but only what is used for prayer. As for what you do not directly handle during prayer, its purification is not obligatory. And for what is feared to be damaged by water, it suffices to purify it by wiping.