Sap/resin has stained brickwork.

[divegirl]

Well as above really, I stupidly left some wood on top of my brand new retaining wall last year and over the winter this black/brown stuff has leaked out and run down the wall! The cement [between the bricks] has gone black....I tried scrubbing it with bleach but it didn't work.
Anything else I can try?

Lisa x

ps will get back to any answers later as I'm off out for lunch :0)

[rowanwitch]

You need to disolve any remaining resin first try turps on a softish wire brush then wash with something like sugar soap

[marden40]

your main problem here is getting it to look right........cleaning the area could get rid of the stain but a clean patch on the wall could look just as bad as the stain........even cleaning a patch on brand new brickwork can stand out, you are probably going to need to do the whole wall.....you could try patio cleaner as these are designed for sap etc, be sure to wear all the relevant safety gear whatever you try. another option, if its only the joints, is to rake out the offending mortar and re-point the area with new.

[The Builder]

To avoid the "patching" that Marden mentioned, think about renting a power washer with a sand-blasting attachment, and do the whole wall.

[divegirl]

Wow....what a lunch that turned in to lol.

Thank you all for your advice. I'll let you know how I get on.

Lisa x