I don't know. I don't know anyone who has a wheelchair to be honest.

How about, you smash my knee caps, and I'll let you know what benefits I get?

I pay charities online or by post and always tell people on the street or at the door That I do this.
I really especially don't trust students dressed up with buckets claiming to be collecting for charities !
Half of it probably ends up being pisssed away down the union on awful drinks !!

Ask them where your share is and when they say you aren't owed anything just scream thief!

or

Tell them you contribute yourself to just one charity personal to you.

This is how I do it.

Tell them you already have what they are selling. Then pick your nose, right in front of them and flick the bogey on the floor.

No one has ever had a come back to that.

"...flick the bogey on the floor."

Why on the floor when there is a perfectly good target within range?

It really is as easy as 'Nah you're alright' with headphones in as soon as they look at you.

Or interrupt them while they are talking and look shocked and say loudly 'NO, I DON'T WANT TO DONATE TO A CHARITY TO SUPPORT PAEDOPHILES' LEGAL COSTS'

just shake your head as soon as they look at you and keep walking

Look moody and say I'm in a rush and quickly walk away.
Or cross the road before you get near them.

these work for me