I recently started renting a room from a homeowner with multiple pets which I'm allergic to. The entire house is full of dander, my clothes, carpet, etc. are already covered in it. What are the best ways to get rid of it all? What steps can i take to keep my room dander-free?
For people who want to live with pets, but have perhaps a mild allergy, my recommendation would be to vacuum frequently with an electric vacuum that includes a HEPA filter and a furniture brush attachment, install quality filters in the home ventilation system, and run a quality room air filter in the bedrooms. Steam clean carpets, upholstered furniture and other surfaces as often as practical. If the pets are of a kind that can tolerate it, washing, brushing and grooming them regularly can be somewhat useful to control shedding. (Bathing is of little if any use with cats, as the allergen is in the cat's saliva, rather than the hair or 'dander', and a washed cat will immediately embark on an epic grooming mission to remove the scent of shampoo! It's also not particularly good for them to be frequently bathed.)
For someone who is living with a major allergy to another person's pets, there is no perfect solution. Cleaning will be a help, but it's impossible to totally 'de-hair' a house in which pets are currently living (and not easy in a house which has had pets in the past, if there are deep pile carpets..)
You may find some relief by adding filters to the heat/ac outlets in your room, changing clothes (perhaps even showering) after spending time in the main areas of the house, and running a HEPA or similar air filter, and perhaps a humidifier, in your room. You can steam clean the carpets in your room, particularly with an allergy-specific cleaner, and wash your bedding often to help prevent too much allergen build up. You may also wrap your pillows, duvet or mattress in allergy specific covers to prevent allergens from infiltrating them.
Normally, that should not be such a big problem, if the owner of the pets would take care of them properly - including grooming and trimming.
If the homeowner does not care about cleaning his pets and his house, you are in a place which is dangerous for your health. Additionally, you are likely to start a "full-time job" caring for the pets and for the apartment. Are you going to be paid for that?
My best answer on this case is: find another place to live. This one does not sound worth living in.
For particular / exceptional cases, you can use a lint remover. It is a device to which the hairs will stick. If it is paper-based, you just peel the used paper to release a new fully working one. If it is plastic based, just wash it and dry it, before using it again.