It's a bit faster if you have 2 computers and 2 accounts....
Once computer / account is the cloak and lich form as suggested above or trap box. The other computer / account does the healing. 2 second cross heals vs 4 to 5 second bandages. This gives twice the amount of bandages applied in the same amount of time, therefore the chance for faster healing gains.
At higher levels you might have to use the 2 computer / accounts and try and resurrect a ghost. The ghost always rejects the resurrection, the healer gets skill gain. This is slower but works well at high levels.
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