...depends on how much $$ u have...kerosene will do a decent job, but kerosene then rinse wit hcontact-cleaner is best...
note: whenever u hv seals start to 'weep' leak, but r still in that 'going bad' stage, often u can get some more life out of them by:
gently remove the dust and oil seal, slide them down the leg, thouroughly spray out everything with contact-cleaner, coat all with a THIN film of high-qulaity silicon grease, and reassemble, then coat the leg itself about 4 inches with a THIN film of that same grease, then pump the bike up and down...often this will instill several more hours out of the seals b 4 they begin really leaking, sometime it 'cures' them for quite awhile...
emergency fix: the alcohol in auto power-steering fluid/etc will also make the seals' rubber swell, but i would not put power-steering fluid in my legs unless it was a ratbike/emergency...