coolant reservoir weirdness

Drained my coolant today; Last coolant change would have been done by PO(I got the bike a year ago this past November). When I got to the bottom of the reservoir (under right side cover), Some black liquid come out -- kind of like black ink, maybe slightly diluted. My 87 has the black reservoir. I took a cloth, fished it in, and then used long-bladed screwdriver to get as much of the remaining drops of liquid out of there as possible. My question: Should I be concerned/looking for a new reservoir, or just let it be?

Flush it out well, and consider replacing the hose going to the radiator. The black gook is probably dissolved hose. The hose is now > 22 years old and has done well to last this long. They like to dry-rot and crack near where they connect to the radiator overflow. When they do that - coolant will go down to the recovery tank, but not get sucked back into the system.

I'd also suggest replacing the radiator cap (cheap..) It has two valves in it that are probably plugged up, and two gaskets on it that have probably perished. It's also done good duty for 22 years and a new one would be a good thing to do.

Thank you, Don. Dissolved hose certainly makes sense. Will take your advice.