jayare
I have used Airplane Stripper to strip paint off of older - 1960's - American Racing Aluminum Rims in the past and alot of metal parts in my resto days. You NEED to try it. It will save you alot of time and will get you down to the original metal without sanding into the metal.
It could take several applications, but it will get you down eventually. Auto Zone or most auto parts houses has it, don't get the spray can version. Get the quart or gallon size version, reusable china bristle paint brush cheap one, 1- 2" size, from Home Depot, good chemical resistant gloves, a metal pan to put it in and if you keep old brushes, toothbrushes, etc. they work very well also.
You should apply a mixture of baking soda and water when done to neutralize the acid from the surface you are stripping. The baking soda not be thick, but white in color. Truthfully, rinsing the part real good does the trick also. Follow the directions as far as ventilation is concerned also, this sh*t can hurt you. Also, if you rinse your hands or keep the stuff off your hands you don't need the gloves.
Let me tell you, I stripped the clear coat someone else had professionally apllied to the rims and all the old paint off the rims and they look great now. I had to stip the clear because it lost it's adhesion - was peeling and was yellowing. Saved me 1,300 clams from not having to buy new ones.
However, if you have rash and you would want to paint the slots back I assume and are not certain of painting the slots, I would have to agree with VNCRUISER. I never painted my rims back on the 60's unit, I left them polished aluminum.
good luck, gurtz