It´s a leftover from production - the reels are probably made via injection die casting and this "grease" is used to separate the product from the cast.
Give it a wash with some soap and hot water, followed by a rinse with hot water and the grease will be gone.
Re wetting agent or stabilizer in tanks - I see not much trouble if you give the stuff a HOT wash just after the final bath, before letting it dry.
This way the wetting agents will be washed off and formaldehyde from stabilizer will evaporate (instead of settling on the reels and intervening with your developer next time you use it).
Before you use the new reels, check them carefully for ridges in the guiding rails - they are not uncommon with plastic reels. Remove them and film will load easily. If the reels squeaks there might be ridges on the core of the reels...
After a few years of usage the tank will begin to leak - now it´s time to replace the red lid with a new one. It´s cheap (cost in Germany is 1,60EUR) and Mom´s good damask cloth on the table will be safe from Rodinal droplets or PcatHD stains. ,-)