lesept:
Here is what I'd suggest:unsigned long Clocktime;
byte Tenhours, Hours, Tenminutes, Minutes, TenSeconds, Seconds;
I would suggest being more consistent with your capitalization. To you, the difference between Variablename and VariableName might not matter, but to the compiler it very much does matter, and if you use one system for all of your variable names, that will make things easier for yourself and anyone else who wishes to read or modify your code.