Petroleum products can degrade the plastic that your cube is made out of, which will shorten the life-span of your cube. Also, petroleum jelly is goopy and yucky, and it will dissolve the adhesive on your stickers.
I've been using cube lube, which is a silicone liquid. It's easy to apply (don't have to disassemble the cube or wait for it to dry), it's inexpensive, and it makes an amazing difference in how your cube spins. It goes on liquid, and then dries to leave a fine film of wax-like silicone on the moving parts of your cube. The problem is finding it. I used to buy it at
www.cubelube.com, but I placed an order last month and the product still hasn’t arrived. Meanwhile, I’ve emailed them several times to find out if it’s a lost or delayed shipment and still haven’t gotten a response. I don’t know whether or not they’ve gone out of business, but I no longer see them as a viable source.
If anybody knows where to get a reasonable facsimile, I’d appreciate the tip.