Clutch worn out?

The bike has been running fine until today. I go to bump start it and there is resistance but the engine doesn't turn over. When the clutch lever is pulled in, the rear wheel freewheels with no drag. If I pedal from a standing start, the engine does turn over so it's not seized up. I checked the clutch cable adjustment and it's fine. When I ride the bike I don't use the clutch much as it's all open road riding, so it shouldn't have worn out but maybe it has from the starting procedure and initial engagement after pedaling up to speed.

Other than the clutch cable, is there anything else to check and adjust? Or I should look to order new clutch material and make a new contribution to the money pit that is the HT bike.

As luck would have it, I went into the garage this morning and there was a pool of gas under the bike. Looks like the carb is leaking and almost a whole tank of gas leaked out overnight. It's one of the newer style carbs with an on/off valve on the carb and red air filter cover. So I'd guess that gas has got on the clutch pads and that's why it's slipping. Thanks for all the advice. No time today to get out and buy brake cleaner but that's what I'll try first to fix the clutch. Not sure yet where the gas is leaking from.