In reply to Pedro50:
Self-amalgmating tape from your local DIY store. However, I've had more success with some brands than others - the best seems to be 'Tape Mammoth SOS Repair Tape'! Alternatively, a friend of mine uses black Stixall
http://www.everbuild.co.uk/stix-all - it gives you a similar finish to the grip on Grivel tools, e.g. the Master. Not tried it on my tools yet, but think I will.
Edit: although having re-read your original post I guess you're not going to be cranking some overhanging horror-show with those tools so the Stixall might be OTT
Post edited at 21:04