You will need carded wool, hot water and soap. Dip your fingertip in soap and rub just a little on a piece of wool. Wind it into a ball:
Dip it quickly in hot water and roll between your palms:
Ball? you think... Looks more like a woollen pacman:
Here´s how to fix it: Put more soap on the weird looking ball, and wind a thin layer of wool around it.
The soap works like glue.
Roll it between your palms again, really light handed first..
and then firmer. There´s your ball!