Small 45 degree blanking plate on drain - 50+ years old

[cumfy]

I've located a blockage in my very very old drains (ground floor flat)(waste water not toilet).

The most logical way of getting at it seems to be to remove what I can only describe as a "45 degree blanking plate", 3 inches x 2 inches which is on a 90 degree bend as the pipe comes out of the base of the external wall.
A snake would then have a straight run at the blockage, 2m max, no bends.

However, I'm concerned it'll be rusted solid and I don't want to break it. It looks circa 1920.

Anyone had any experience of attempting something like this ?

 

[mfarrow]

If you're concerned about breaking it, try soaking it in PlusGas first, repeating applications over several days before trying to get the cap off.

Cast components are prone to breaking quite easily, and you are wise to be cautious.

 

[cumfy]

Thanks, I'd not heard of PlusGas, but will give it a go.