Aidan,
Tell me about it. I used to be keen on cacti and I still have a few species including
Opuntia (Tunilla) soehrensii.
I only keep it out of sentiment as I think it's the most evil plant I've ever come across

. The only way to detatch it from your skin is by using a comb to avoid touching it, I keep one next to it just-in-case.
Otherwise it's like Br'er Rabbit fighting the Tar-Baby.
Cheers,
T.