Colored cellophane maybe? Either patch the hole or rip it all off and recover it entirely?
Don't use regular cellophane as you will start a fire. You need to get an actual theater light gel. The 100w colored floods get hot. If you want to stick to standard bulbs building a coffee can style enclosure around the light with a gel on the front will be a vast improvement. You can go with the higher efficiency 45w floods that produce about the same amount of lumens.Colored cellophane maybe?