We were "rained on" by a newly trimmed pine tree. Not much seemed to work and the sticky gunk got everywhere!
This combo worked effortlessly:
Tree sap is essentially a wax. To remove you need a bucket a couple of squirts of washing up liquid rubber gloves a sponge and hose. The water in the bucket must be very hot this is to melt the sap (wax). Apply the mix with the sponge have the hose running and hose it off immediately. It is that simple.