"brute force" and custom charset questions

[jnet]

these are special characters interpreted by bash. You need to either (single) quote them or escape them.

I tried the following:

Code:

./oclHashcat-plus64.bin -a 3 --remove -r rules/custom/pix_salt.rule  -n 40 --gpu-loops=1000 -o solved/pix.solv -m 2400 hashes/pix.hash -1 ?l?d -2 ?d'!?@#$%&' ?u?l?l?l?l?l?1?2

and got this: Syntax error: ?d!?@#$%&

I also tried putting single quotes around only ! and ? and still received the syntax error. What is the escape character?

edit- Using \ as an escape also results in syntax error.