As Dunk said deffo the oil seal around the shaft of the distributor, it's diy'able (few quid from toyota) but you need to be very careful of marking the position of the distributor so you can replace it and not effect the timing. You might need a timing light to re time it if you are a bit cack handed when doing it.   Engine cleaner, tooth brush with a towel underneath to minimise the fluid getting in the spark plug wells, will bring up the aluminium bits a bit, that's where i'd start. Or you c