Rename the info.txt to addon.txt
The reason for this is because anything Lua related is most likely broken and if Garry hadn't done this there'd be masses of idiots trying to play with old, broken addons. I would recommend you avoid doing this to your SWEPs and custom entities unless you know how to fix them.
If they're models, go into their folders, take the materials and models folders and put them in garrysmod/garrysmod and look for them in the browse>garry's mod directory of the spawn menu
If they're tools, you can try taking them out and putting them in the garrysmod/garrysmod directory but it may not work, you might have to wait for it to be uploaded to the workshop
That's a really bad idea because you'll most likely forget where all of the files are located if you wish to remove one certain thing. Proper addons are packaged the way they are for a reason.