Remove all debris to reduce risk of fungal diseases and to keep plenty of air flowing around the plants. Wrap pots with horticultural Fleece or newspaper to help prevent the plants' roots freezing.
Come the following spring, you can give the plants a hard prune which will rejuvenate them - simply snip off the stems down to about 1 inch.
Tender plants will often recover from frost damaged stems by shooting from the base, but are unlikely to regenerate if the roots have been frozen. If appropriate line your Greenhouse with bubble-wrap to help protect vulnerable plants.