Can I access the plusnet email blackhole externally

[#1]

Hi guys
I have an externally registered domain that normally has a catch all email forwarder pointing at my plusnet account. Recently I have noticed that one or two of my email addresss from this domain are starting to get a few spam emails.
One solution I thought of was to set the email forwarders to send mail addressed to the compromised addresses directly to the plusnet blackhole.
I just wondered if plusnet consider this acceptable as I suppose technically it isn't mail addressed to one of their domains?
Cheers

[#2]

Why use the black hole? If you forward it to something like email.blocked@mailbox.inv (i.e a totally invalid domain) it will generate an undeliverable email message back to the sender.

[#3]

Thanks for the suggestion Jelv.
I would still like an answer from a plusnet staffer when someoene gets a minute.
Cheers

[#4]

To be honest, there is no technical reason why you couldn't.
However, the preferred solution is not to. This is traffic we shouldn't need to handle and whilst we are not talking masses of traffic, it's all items that build up and up which can have  network impact.

[#5]

Thanks for the response Phil
Am I right in assuming that the difference between forwarding them to the black hole or similar address elsewhere and Jelv's suggestion of any invalid address is that the black hole is valid and does not therefore produce an undeliverable message?
After all spammers use other people's addresses who would it seems receive the undeliverable messages generated by an invalid address.