It is illegal to release a grey squirrel back into the wild!
A trapping comb will help you with the removal or dispatch of the squirrel. Using one or two combs to persuade the squirrel to move along the trap. The second comb is placed between the first comb and the squirrel as soon as possible. Repeating until the squirrel is held at the far end of the trap. With the squirrel trapped you can easily place the Hessian sack over the end of the trap or dispatch with a gun without the squirrel moving around.
Shooting at close range through the trap with an air gun is an equally humane method of dispatch. However, air rifles may be cumbersome to use but some air pistols are powerful enough to achieve an instant kill. There is a risk of injury to the operator as the wire mesh or the ground may deflect the pellet. Blood in the trap may deter other animals from entering and pose a risk of squirrel pox disease transfer where both red and grey squirrels are present. Drowning is not a humane method of dispatch and is illegal.
A medium weight Hessian sack is used to extract the squirrels from the trap. If the sack is too thin there is a high risk of being bitten or scratched through the fabric, and if too heavy it will be difficult to control the movement of a squirrel inside. Polythene sacks have an open weave and are unsuitable. After first checking that there are no holes in it, the open end of the sack is placed around the trap exit door and the width of the sack rolled up to form a tunnel. The exit door is opened and captive squirrels are driven, one at a time, into the sack and the
exit door closed. When squirrels are reluctant to leave the trap, e.g. in poor light conditions, they can be encouraged to move into the sack by blowing on the base of their tail. The operator should position themselves so as not to deter the squirrel from entering the sack. The squirrel is then moved into the corner of the sack and with the head positioned carefully within the corner, killed rapidly and humanely by a single blow to the back of the head with a blunt instrument.