I've only ever found one method for treating this that works. Bathing. You need to get a tupperware tub and fill it with room-temperature water almost comlpetely full. Leave a small gap so there is enough air space between the water level and the lid. This will encourage your royal to submerge his head completely, but will also allow him to breath. Make a couple of air holes in the lid so the air there circulates.
Then place your royal in the water and put the lid on. Ensure that there is still a cm gap between the water surface and the lid - the water level will rise at this point obviously. Leave him in there for 45 mins to an hour, and monitor him carefully. Don't be suprised if he stays under the water longer then you would expect, they can hold their breaths a long time.
(I had to do this a few times for an ATB I had a while back, every time he shed.)
When he has been in there for an hour, veeeeery gently work at the retained shed on the tail with a finger nail. If it is sliding off with no effort then remove it. If it is still retained, then repeat this process the following day. You will eventually work the retained tail shed loose, but how long this takes will depend on how many layers have built up.
For the eyecap, the same method should be used, but I would stear clear of trying to remove it manually yourself. By having the water level in the tupperware tub so high, your snake will be submerging his head and the hope is that just by soaking the cap will will work it's way off by itself after a few daily bathes. There is a danger with eye caps that if you rip it off you can damage the eye.
If after four or five daily baths like this, the eye cap is still retained, get a rubber finger cap - the ones from post offices to help grip when turning pages:
After a good long bathe, genty rub across the surface of the eye with this. This should help remove the eye cap, while minimising any potential damage to the eye.
Good luck and let us know how you get on.