It's only because I'm a complete numpty too when it comes to mechanical things!!!
OH says you could use vaseline as it will act as a grease, if you want to save some dosh! He said thejockey wheels shouldn't need too much due to short term movement, so a fingerful of vaseline either side should do the trick!!
Mine had seized and the OH used a sticky spray oil intended for chainsaws. Sprayed straight in the hole. Then he wound it in and out a few times and it's quite slippy and easy to use now.
My OH did the same with his flatbed trailer, but I think he used hydrolic oil, just poured it in. Jockey wheel would not move before but works fine now. If you need a grease gun & cartridges, we get ours from TH Whites.
Oil and grease are different (one is thick, one is thin). If it is the raise and lower mechanism on the jockey wheel that has an oil hole, then just some engine oil will do the trick. 3 in 1 will do it too or if you have any, bike chain lube. Any spray lube will also be fine, but grease pushed into that little hole will just block the hole up.
If it were the axle of the wheel itself you were talking about, then just any old axle grease you find around the garage or farm yard.
Vaseline is often mentioned, probably because it always readily available. As a last gasp emergency it will do, but it is a moisturiser, not an axle or tow ball lubricant, you'd be almost as well served using Neetsfoot oil!
As for Lithium grease, it's just thick / sticky bearing grease. Nothing special or exotic.
that is really helpful - thank you. An idiots guide to grease and oil!
It was the solid/liquid thing that had me confused - its the raise/lower mechanism, as I thought liquid would be best. I will try sticking some 3 in 1 down there as I have some to hand.