an oven in the northwest corner in fengshui is called fire in the heaven, it is bad for your financial health, and all men in your life (even if they do not live with you like family and love ones) would either be sickly or cannot function well. i do not think that there is a remedy for this, except move the oven, and change the color. because orange is also fire in fengshui. and fire cannot occupy the northwest section of your house.
i know that you want a quick fix or a cheap solution to your problem, but in fengshui there are just some things that cannot be solved when you have little resources.
the oven/ stove/ kitchen/ rice cooker/ boiling kettle are all responsible for attracting wealth into your life, it just depends on how you locate them in your house.
if your apartment is small, i do not think that you really have choice. bec fengshui basically depends on chi or energy that occupies space - the more space your house have, the more chi it contains. but you still need to see what kind of chi/ energy is in your small house, bec it can be good and it can be bad for you. fengshui practitioners know how to measure and calculate for this and use these to your advantage - to make your life easier.
the techniques or formulas are not that simple to put them all here. better if you can buy a book by lillian too, eva wong, peter leung or joey yap. so you can do fengshui yourself.
if you know fengshui, you will understand why remedies do not work. they cause more harm than good, complicating your life more. like a windchime hanged by the door attracts spirits, while a bagua can be fatal to the occupants or to the neighbors.
if you are a woman, there will still be problems caused by this, but it will be worst if you are man.\
note: for people who answered that northwest is metal and thus should be painted with orange or red. you should review your fengshui again! northwest is heaven part, and is represent by the father/ male. if you put the fire element here, there will be "fire in the heavens", which is a big no-no in fengshui. and it can cause harm to the father or men in the house. remember, fire melts and do not enhance metal. fire basically destroys metal or heaven or the man of the family!