A bottle of Gum Arabic Solution has developed some clot of material in the bottom of the bottle. Is it OK to use?

We do at times get some sediment coming out of solution, so if that's what it is it's not anything to get worried about.

The only other possibility is that it could be mould. It certainly shouldn't be because we add preservatives to prevent mould growth. If it is mould growth it will smell bad and should be returned to your supplier for replacement.