How to remove stuck Shimano Hollow-Tech bottom bracket cups? When I tried to remove the bottom bracket bearing cups using the BB tool it was very hard to move or it's just stuck. Tried WD40 then slowly tapping the tool using a mallet didn't work. To cut the story short, the tool moves but the cups didn't. Other to remove these? As you can see in the picture, the tool left marks on the cups.
If you want to re-use these cups without a lot of tool marks, using a high quality removal tool that fits the cup splines closely is advisable. A thin sheet of plastic between the BB cup tool and the cups can take up space, give a firmer purchase on the grooves in the cup and protect the cups from tool marks. (Credit to John Cannings of GCN for this tip.)

Make sure the tool is all the way on the cup and held there firmly. If you tool has a hole through the middle you can use a long bolt, large diameter washers and a nut to hold the tool on. (Similar to using a QR to hold a cassette lockring tool in place.)    

Make sure you are turning the tool the correct way. The right hand side is left hand threaded, so to loosen: clockwise on the right, anticlockwise on the left. (I doubt you are getting this wrong as the HT cups have the tighten direction printed on them, but I included it for future readers.)