Using antibacterial spray and a cloth to remove impurities from surfaces

Q: I was wondering if it will be permissible to use antibacterial spray such as detol or zaflora to remove najasah on surfaces like doors, door handles and radiators by spraying and then drying with tissue paper.

I also read in a fatwaa that if the spray causes side effects you cannot use it. The sprays I have say they cause eye irritation. Does this mean I can't use it. Can you please respond as I need to know cause it will cause me alot of difficulty cleaning the radiators without spraying them and having to use a wet piece of tissue then a dry one. I also feel if I use a wet cloth I will just spread najasah everywhere.

Meaning of the Hadith "The city of Jerusalem will flourish while the the city of yathrib (Madina) will be in ruins"

Q: In one Hadith it is somehow narrated that the city of Jerusalem will flourish while the the city of yathrib (Madina) will be in ruins. The ruined state of Madina will be when the huge war comes. Please could you explain what the flourishing state of Jerusalem is and ruined state of Madina.

Selling cigarettes

Q: I live with my grandparents and they have a shop which sell mostly biscuits & they also sell cigarattes! (According to some sholars in my country cigrattes are makrooh, while I have heard some Arab scholars say its haraam).

I want to be on the safe side so, as I live in their house my concern is I use electricity/internet to learn as I learn online! Will my online earning be halal if I pay them later on for electricity/internet I use?