Today I took off a wheel on my boat's trailer for the first time since I bought it a year ago. I was pleased to find a "Bearing Buddy" and alot of grease. The grease is green (like the color of oxidised copper) and I have no idea what kind it is. I just bought a new grease gun and it came with "multi purpose lithium grease". Would it be ok to just pump some of that in on top of the old grease? I don't want to take it apart and re-grease the whole thing...I'm going to be selling it in a few months.